Bump CSSUoB/pr-auto-updater from 2.1.2 to 2.2.4 (#836)

Bumps [CSSUoB/pr-auto-updater](https://github.com/cssuob/pr-auto-updater) from 2.1.2 to 2.2.4.
- [Release notes](https://github.com/cssuob/pr-auto-updater/releases)
- [Commits](CSSUoB/pr-auto-updater@v2.1.2...v2.2.4)

---
updated-dependencies:
- dependency-name: CSSUoB/pr-auto-updater
  dependency-version: 2.2.4
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]

.github/workflows/pr-auto-update.yml

@@ -17,7 +17,7 @@ jobs:
           app-id: ${{ vars.PR_AUTO_UPDATE_CLIENT_ID }}
           private-key: ${{ secrets.PR_AUTO_UPDATE_PRIVATE_KEY }}
 
-      - uses: CSSUoB/pr-auto-updater@v2.1.2
+      - uses: CSSUoB/pr-auto-updater@v2.2.4
         env:
           GITHUB_TOKEN: ${{ steps.generate-token.outputs.token }}
           PR_FILTER: 'labelled'