Version section update (#38937)

* Version section update 

Added a little bit more information on the version section. Currently, it only discusses the v1 which is not valid anymore.

* Update docs/how-to-guides/themes/theme-json.md

* Update docs/how-to-guides/themes/theme-json.md

Co-authored-by: André <583546+oandregal@users.noreply.github.com>

docs/how-to-guides/themes/theme-json.md

@@ -148,10 +148,10 @@ This specification is the same for the three different origins that use this for
 ```
 
 ### Version
+This field describes the format of the `theme.json` file. The current version is [v2](https://developer.wordpress.org/block-editor/reference-guides/theme-json-reference/theme-json-living/), [introduced in WordPress 5.9](https://make.wordpress.org/core/2022/01/08/updates-for-settings-styles-and-theme-json/). It also works with the current Gutenberg plugin.
 
-This field describes the format of the `theme.json` file. The current and only version is 1.
+If you have used [v1](https://developer.wordpress.org/block-editor/reference-guides/theme-json-reference/theme-json-v1/) previously, you don’t need to update the version in the v1 file to v2, as it’ll be [migrated](https://developer.wordpress.org/block-editor/reference-guides/theme-json-reference/theme-json-migrations/) into v2 at runtime for you.
 
-WordPress 5.8 will ignore the contents of any `theme.json` whose version is not equals to the current. Should the Gutenberg plugin need it, it'll update the version and will add the corresponding migration mechanisms from older versions.
 
 ### Settings