doc: remove cert-manager from getting-started

Signed-off-by: Thomas Schuetz <[email protected]>

docs/content/en/docs/snippets/tasks/install.md

@@ -40,18 +40,6 @@ The full list of available flags can be found in the [helm-charts](https://githu
 > **Note:**
 Installation of the Lifecycle Toolkit version 0.6.0 and lower is not supported via helm charts.
 
-<details>
-<summary>Install Cert-Manager (0.6.0 and earlier)</summary>
-
-You can install *cert-manager* with the following commands:
-
-```shell
-kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.11.0/cert-manager.yaml
-kubectl wait --for=condition=Available deployment/cert-manager-webhook -n cert-manager --timeout=60s
-```
-
-</details>
-
 <details>
 <summary>Install Keptn using Manifests</summary>