feat(content-docs): last_update front matter (#7461)

Co-authored-by: Joshua Chen <sidachen2003@gmail.com>
Co-authored-by: sebastienlorber <lorber.sebastien@gmail.com>

website/_dogfooding/_docs tests/doc-with-last-update.md

@@ -0,0 +1,7 @@
+---
+last_update:
+  author: custom author
+  date: 1/1/2000
+---
+
+# Doc With Last Update Front Matter

website/_dogfooding/docs-tests-sidebars.js

@@ -22,6 +22,7 @@ const sidebars = {
     'test-draft',
     'doc-without-sidebar',
     'doc-with-another-sidebar',
+    'doc-with-last-update',
     {
       type: 'category',
       label: 'Tests',

website/_dogfooding/dogfooding.config.js

@@ -30,6 +30,7 @@ const dogfoodingPluginInstances = [
       // Using a _ prefix to test against an edge case regarding MDX partials: https://github.com/facebook/docusaurus/discussions/5181#discussioncomment-1018079
       path: '_dogfooding/_docs tests',
       showLastUpdateTime: true,
+      showLastUpdateAuthor: true,
       sidebarItemsGenerator(args) {
         return args.defaultSidebarItemsGenerator({
           ...args,

website/docs/api/plugins/plugin-content-docs.md

@@ -281,6 +281,7 @@ Accepted fields:
 | `slug` | `string` | File path | Allows to customize the document url (`/<routeBasePath>/<slug>`). Support multiple patterns: `slug: my-doc`, `slug: /my/path/myDoc`, `slug: /`. |
 | `tags` | `Tag[]` | `undefined` | A list of strings or objects of two string fields `label` and `permalink` to tag to your docs. |
 | `draft` | `boolean` | `false` | A boolean flag to indicate that a document is a work-in-progress. Draft documents will only be displayed during development. |
+| `last_update` | `FileChange` | `undefined` | Allows overriding the last updated author and/or date. Date can be any [parsable date string](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/parse). |
 
 </APITable>
 
@@ -288,6 +289,10 @@ Accepted fields:
 type Tag = string | {label: string; permalink: string};
 ```
 
+```ts
+type FileChange = {date: string; author: string};
+```
+
 Example:
 
 ```md
@@ -306,6 +311,9 @@ keywords:
   - docusaurus
 image: https://i.imgur.com/mErPwqL.png
 slug: /myDoc
+last_update:
+  date: 1/1/2000
+  author: custom author name
 ---
 
 # Markdown Features