Docs: Add version command (#7719)

* Docs: Add version command

* adding to

website/source/docs/commands/version.html.md

@@ -0,0 +1,24 @@
+---
+layout: "docs"
+page_title: "version - Command"
+sidebar_title: "<code>version</code>"
+sidebar_current: "docs-commands-version"
+description: |-
+  The "version" command prints the version of Vault.
+---
+
+# version
+
+The `version` command prints the Vault version:
+
+```
+$ vault version
+Vault v1.2.3
+```
+
+It can also be printed by adding the flags `--version` or `-v` to the `vault` command:
+
+```
+$ vault -v
+Vault v1.2.3
+```

website/source/layouts/docs.erb

@@ -184,6 +184,7 @@
               ]
             },
             'unwrap',
+            'version',
             'write',
             'token-helper'
             ]