Bump CSSUoB/pr-auto-updater from 2.2.4 to 2.3.1 in the gh-actions group (#84)

Bumps the gh-actions group with 1 update: [CSSUoB/pr-auto-updater](https://github.com/cssuob/pr-auto-updater).


Updates `CSSUoB/pr-auto-updater` from 2.2.4 to 2.3.1
- [Release notes](https://github.com/cssuob/pr-auto-updater/releases)
- [Commits](v2.2.4...v2.3.1)

---
updated-dependencies:
- dependency-name: CSSUoB/pr-auto-updater
  dependency-version: 2.3.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: gh-actions
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/autoupdate.yaml

@@ -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@v2.2.4
+      - uses: CSSUoB/pr-auto-updater@v2.3.1
         env:
           GITHUB_TOKEN: ${{ steps.generate-token.outputs.token }}
           PR_FILTER: 'labelled'