Add support for CSVs in template --api-versions arg

This commit changes the template sub-command argument
`--api-versions` from `StringArrayVarP` to `StringSliceVarP`,
to allow support for comma separated variables. This will allow
users to use a syntax such as `--api-versions one,two,three` over
`--api-versions one --api-versions two --api-versions three`.

Fixes: #11485

Signed-off-by: Ryan Drew <ryan.drew@isovalent.com>

cmd/helm/template.go

@@ -181,7 +181,7 @@ func newTemplateCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 	f.BoolVar(&skipTests, "skip-tests", false, "skip tests from templated output")
 	f.BoolVar(&client.IsUpgrade, "is-upgrade", false, "set .Release.IsUpgrade instead of .Release.IsInstall")
 	f.StringVar(&kubeVersion, "kube-version", "", "Kubernetes version used for Capabilities.KubeVersion")
-	f.StringArrayVarP(&extraAPIs, "api-versions", "a", []string{}, "Kubernetes api versions used for Capabilities.APIVersions")
+	f.StringSliceVarP(&extraAPIs, "api-versions", "a", []string{}, "Kubernetes api versions used for Capabilities.APIVersions")
 	f.BoolVar(&client.UseReleaseName, "release-name", false, "use release name in the output-dir path.")
 	bindPostRenderFlag(cmd, &client.PostRenderer)