[BUG] Honor stdin for config k3d cluster create -c

[kameshsampath]

When scripting to create k3s cluster with k3d via config file, I am not able to pass the config via stidin

What did you do

cat <<EOF | k3d cluster create -c -
apiVersion: k3d.io/v1alpha4
kind: Simple
metadata:
  name: my-cluster
servers: 1
agents: 2
image: rancher/v1.24.3-k3s1
ports:
  # Drone CI
  - port: 127.0.0.1:30980:30980
    nodeFilters:
      - agent:*
  # Gitea
  - port: 127.0.0.1:30950:30950
    nodeFilters:
      - agent:*
  # Argo CD
  - port: 127.0.0.1:30080:30080
    nodeFilters:
      - agent:*
registries: 
    name: "${reg_name}"
    host: "0.0.0.0"
    hostPort: "${reg_port}"
    volumes:
      - "${PWD}/.k3s/registry":/var/lib/registry
EOF

What did you expect to happen

k3s cluster to be created

Screenshots or terminal output

FATA[0000] Failed to stat config file -: stat -: no such file or directory

Which OS & Architecture

arch: aarch64
cgroupdriver: cgroupfs
cgroupversion: "2"
endpoint: /var/run/docker.sock
filesystem: extfs
name: docker
os: Docker Desktop
ostype: linux
version: 20.10.17

Which version of k3d

k3d version v5.4.4
k3s version v1.23.8-k3s1 (default)

Which version of docker

Client:
 Version:           20.10.16
 API version:       1.41
 Go version:        go1.17.10
 Git commit:        aa7e414
 Built:             Wed Jun  1 21:26:39 2022
 OS/Arch:           darwin/arm64
 Context:           default
 Experimental:      true

Server: Docker Desktop 4.11.1 (84025)
 Engine:
  Version:          20.10.17
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.17.11
  Git commit:       a89b842
  Built:            Mon Jun  6 23:01:01 2022
  OS/Arch:          linux/arm64
  Experimental:     false
 containerd:
  Version:          1.6.6
  GitCommit:        10c12954828e7c7c9b6e0ea9b0c02b01407d3ae1
 runc:
  Version:          1.1.2
  GitCommit:        v1.1.2-0-ga916309
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

Client:
 Context:    default
 Debug Mode: false
 Plugins:
  buildx: Docker Buildx (Docker Inc., v0.8.2)
  compose: Docker Compose (Docker Inc., v2.5.1)
  extension: Manages Docker extensions (Docker Inc., v0.2.8)
  sbom: View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc., 0.6.0)
  scan: Docker Scan (Docker Inc., v0.17.0)

Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 55
 Server Version: 20.10.17
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 io.containerd.runtime.v1.linux runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 10c12954828e7c7c9b6e0ea9b0c02b01407d3ae1
 runc version: v1.1.2-0-ga916309
 init version: de40ad0
 Security Options:
  seccomp
   Profile: default
  cgroupns
 Kernel Version: 5.10.104-linuxkit
 Operating System: Docker Desktop
 OSType: linux
 Architecture: aarch64
 CPUs: 4
 Total Memory: 15.61GiB
 Name: docker-desktop
 ID: 44I2:KWI6:WBA7:2LZY:EQLX:Q5LS:6ARD:QV6R:QE7E:EWFH:F5LX:DIHR
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 HTTP Proxy: http.docker.internal:3128
 HTTPS Proxy: http.docker.internal:3128
 No Proxy: hubproxy.docker.internal
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  hubproxy.docker.internal:5000
  127.0.0.0/8
 Live Restore Enabled: false