`version` identifier as metadata field

```
! version: 1.0.0
```

Could be a helpful addition to the default goggle metadata fields.

## Used for what?
* To track and identify different _versions_ of a goggle
* Perhaps Brave Search could regularly check submitted goggle URLs, if a version change is identified, the goggle is automatically refreshed without the need of resubmitting it on every update by the user
* This is how https://userstyles.world/ does it for user stylesheets

Start by locating the default Goggle metadata fields referenced in the issue and review how metadata is documented. Determine the expected behavior for a version value, including whether URL refreshes are part of this change; done should mean the supported metadata and its intended update behavior are clearly defined.

Written by the indexing model from the issue text.