Bump JamesIves/github-pages-deploy-action from 3.7.1 to 4.7.3

Bumps [JamesIves/github-pages-deploy-action](https://github.com/jamesives/github-pages-deploy-action) from 3.7.1 to 4.7.3.
- [Release notes](https://github.com/jamesives/github-pages-deploy-action/releases)
- [Commits](JamesIves/github-pages-deploy-action@3.7.1...v4.7.3)

---
updated-dependencies:
- dependency-name: JamesIves/github-pages-deploy-action
  dependency-version: 4.7.3
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/docs.yml

@@ -14,7 +14,7 @@ jobs:
       run: pip install ford
     - name: Build Documentation
       run: ford docs.md
-    - uses: JamesIves/github-pages-deploy-action@3.7.1
+    - uses: JamesIves/github-pages-deploy-action@v4.7.3
       if: github.event_name == 'push' && github.repository == 'fortran-lang/fpm' && ( startsWith( github.ref, 'refs/tags/' ) || github.ref == 'refs/heads/main' )
       with:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}