Lock AngelDocs to specific version.

[KaiPrince]

Overview

Lock the GitHub action for AngelDocs to a specific version.

Reason for change

This will prevent errors that occur when usage / syntax changes are made to the project before they are updated here. (i.e. what happened last time).

Changes summarized

• Lock to v0.1.

Suggested future tasks

• Replace trigger branch dev with main, once this fix is confirmed.

Checklist

• No new warnings are introduced
• Comments and documentation are up to date
• TODOs resolved or added to issue tracker
• No commented-out code
• This isn't a 'quick-and-dirty' job