Update helm standalone TLS doc for k8s 1.22 (#16029)

Update helm standalone TLS doc for k8s 1.22

The `CertificateSigningRequest` for `v1beta1` API is no longer
available, and now requires the `signerName` parameter.

Many thanks to @DavidRBanks for the helpful notes in
hashicorp/vault-helm#243 (comment)

I tested this on Kubernetes 1.21 and 1.24. I also adjusted the `tr`
command to work better on macOS (and still works fine on Linux).

website/content/docs/platform/k8s/helm/examples/standalone-tls.mdx

@@ -18,35 +18,42 @@ This example can be used to set up a single server Vault cluster using TLS.
 
 ## 1. Create key & certificate using Kubernetes CA
 
-There are three variables that will be used in this example.
+There are four variables that will be used in this example.
 
 ```bash
 # SERVICE is the name of the Vault service in Kubernetes.
 # It does not have to match the actual running service, though it may help for consistency.
-SERVICE=vault-server-tls
+export SERVICE=vault-server-tls
 
 # NAMESPACE where the Vault service is running.
-NAMESPACE=vault-namespace
+export NAMESPACE=vault-namespace
 
 # SECRET_NAME to create in the Kubernetes secrets store.
-SECRET_NAME=vault-server-tls
+export SECRET_NAME=vault-server-tls
 
 # TMPDIR is a temporary working directory.
-TMPDIR=/tmp
+export TMPDIR=/tmp
+
+# CSR_NAME will be the name of our certificate signing request as seen by Kubernetes.
+export CSR_NAME=vault-csr
 ```
 
 1. Create a key for Kubernetes to sign.
 
-   ```bash
-   openssl genrsa -out ${TMPDIR}/vault.key 2048
+   ```shell-session
+   $ openssl genrsa -out ${TMPDIR}/vault.key 2048
+   Generating RSA private key, 2048 bit long modulus
+...................................................................................................+++
+...............+++
+e is 65537 (0x10001)
    ```
 
 2. Create a Certificate Signing Request (CSR).
 
    1. Create a file `${TMPDIR}/csr.conf` with the following contents:
 
-      ```
-      $ cat <<EOF >${TMPDIR}/csr.conf
+      ```bash
+      cat <<EOF >${TMPDIR}/csr.conf
       [req]
       req_extensions = v3_req
       distinguished_name = req_distinguished_name
@@ -67,86 +74,99 @@ TMPDIR=/tmp
 
    2. Create a CSR.
 
-      ```bash
-      openssl req -new -key ${TMPDIR}/vault.key -subj "/CN=${SERVICE}.${NAMESPACE}.svc" -out ${TMPDIR}/server.csr -config ${TMPDIR}/csr.conf
+      ```shell-session
+      $ openssl req -new -key ${TMPDIR}/vault.key \
+          -subj "/O=system:nodes/CN=system:node:${SERVICE}.${NAMESPACE}.svc" \
+          -out ${TMPDIR}/server.csr \
+          -config ${TMPDIR}/csr.conf
       ```
 
 3. Create the certificate
 
    1. Create a file `${TMPDIR}/csr.yaml` with the following contents:
 
-      ```
-      $ export CSR_NAME=vault-csr
-      $ cat <<EOF >${TMPDIR}/csr.yaml
-      apiVersion: certificates.k8s.io/v1beta1
+      ```bash
+      cat <<EOF >${TMPDIR}/csr.yaml
+      apiVersion: certificates.k8s.io/v1
       kind: CertificateSigningRequest
       metadata:
         name: ${CSR_NAME}
       spec:
         groups:
         - system:authenticated
-        request: $(cat ${TMPDIR}/server.csr | base64 | tr -d '\n')
+        request: $(cat ${TMPDIR}/server.csr | base64 | tr -d '\r\n')
+        signerName: kubernetes.io/kubelet-serving
         usages:
         - digital signature
         - key encipherment
         - server auth
       EOF
       ```
 
-      -> `CSR_NAME` can be any name you want. It's the name of the CSR as seen by Kubernetes
-
    2. Send the CSR to Kubernetes.
 
-      ```bash
-      kubectl create -f ${TMPDIR}/csr.yaml
+      ```shell-session
+      $ kubectl create -f ${TMPDIR}/csr.yaml
+      certificatesigningrequest.certificates.k8s.io/vault-csr created
       ```
 
       -> If this process is automated, you may need to wait to ensure the CSR has been received and stored:
       `kubectl get csr ${CSR_NAME}`
 
    3. Approve the CSR in Kubernetes.
 
-      ```bash
-      kubectl certificate approve ${CSR_NAME}
+      ```shell-session
+      $ kubectl certificate approve ${CSR_NAME}
+      certificatesigningrequest.certificates.k8s.io/vault-csr approved
+      ```
+
+   4. Verify that the certificate was approved and issued.
+      ```shell-session
+      $ kubectl get csr ${CSR_NAME}
+      NAME        AGE     SIGNERNAME                                    REQUESTOR                        CONDITION
+      vault-csr   1m13s   kubernetes.io/kubelet-serving                 kubernetes-admin                 Approved,Issued
       ```
 
 ## 2. Store key, cert, and Kubernetes CA into Kubernetes secrets store
 
 1. Retrieve the certificate.
 
-   ```bash
-   serverCert=$(kubectl get csr ${CSR_NAME} -o jsonpath='{.status.certificate}')
+   ```shell-session
+   $ serverCert=$(kubectl get csr ${CSR_NAME} -o jsonpath='{.status.certificate}')
    ```
 
    -> If this process is automated, you may need to wait to ensure the certificate has been created.
    If it hasn't, this will return an empty string.
 
 2. Write the certificate out to a file.
 
-   ```bash
-   echo "${serverCert}" | openssl base64 -d -A -out ${TMPDIR}/vault.crt
+   ```shell-session
+   $ echo "${serverCert}" | openssl base64 -d -A -out ${TMPDIR}/vault.crt
    ```
 
 3. Retrieve Kubernetes CA.
 
-   ```bash
-   kubectl config view --raw --minify --flatten -o jsonpath='{.clusters[].cluster.certificate-authority-data}' | base64 -d > ${TMPDIR}/vault.ca
+   ```shell-session
+   $ kubectl config view --raw --minify --flatten -o jsonpath='{.clusters[].cluster.certificate-authority-data}' | base64 -d > ${TMPDIR}/vault.ca
    ```
 
 4. Create the namespace.
 
-    ```bash
-    kubectl create namespace ${NAMESPACE}
+    ```shell-session
+    $ kubectl create namespace ${NAMESPACE}
+    namespace/vault-namespace created
     ```
 
 5. Store the key, cert, and Kubernetes CA into Kubernetes secrets.
 
-   ```bash
-   kubectl create secret generic ${SECRET_NAME} \
-           --namespace ${NAMESPACE} \
-           --from-file=vault.key=${TMPDIR}/vault.key \
-           --from-file=vault.crt=${TMPDIR}/vault.crt \
-           --from-file=vault.ca=${TMPDIR}/vault.ca
+   ```shell-session
+   $ kubectl create secret generic ${SECRET_NAME} \
+       --namespace ${NAMESPACE} \
+       --from-file=vault.key=${TMPDIR}/vault.key \
+       --from-file=vault.crt=${TMPDIR}/vault.crt \
+       --from-file=vault.ca=${TMPDIR}/vault.ca
+
+   # secret/vault-server-tls created
    ```
 
 ## 3. Helm Configuration