Add HTTP PATCH support for KV key metadata (#13215)

* go get vault-plugin-secrets-kv@vault-4290-patch-metadata

* add kv metadata patch command

* add changelog entry

* success tests for kv metadata patch flags

* add more kv metadata patch flags tests

* add kv metadata patch cas warning test

* add kv-v2 key metadata patch API docs

* add kv metadata patch to docs

* prevent unintentional field overwriting in kv metadata put cmd

* like create/update ops, prevent patch to paths ending in /

* fix kv metadata patch cmd in docs

* fix flag defaults for kv metadata put

* go get vault-plugin-secrets-kv@vault-4290-patch-metadata

* fix TestKvMetadataPatchCommand_Flags test

* doc fixes

* go get vault-plugin-secrets-kv@master; go mod tidy

command/commands.go

@@ -718,6 +718,11 @@ func initCommands(ui, serverCmdUi cli.Ui, runOpts *RunOptions) {
 				BaseCommand: getBaseCommand(),
 			}, nil
 		},
+		"kv metadata patch": func() (cli.Command, error) {
+			return &KVMetadataPatchCommand{
+				BaseCommand: getBaseCommand(),
+			}, nil
+		},
 		"kv metadata get": func() (cli.Command, error) {
 			return &KVMetadataGetCommand{
 				BaseCommand: getBaseCommand(),