Upgrade GitHub Actions to latest versions (#2842)

## Summary

Upgrade GitHub Actions to their latest versions for improved features,
bug fixes, and security updates.

## Changes

| Action | Old Version(s) | New Version | Release | Files |
|--------|---------------|-------------|---------|-------|
| `actions/upload-pages-artifact` |
[`v3`](https://github.com/actions/upload-pages-artifact/releases/tag/v3)
|
[`v4`](https://github.com/actions/upload-pages-artifact/releases/tag/v4)
|
[Release](https://github.com/actions/upload-pages-artifact/releases/tag/v4)
| deploy-docsite.yml |

## Why upgrade?

Keeping GitHub Actions up to date ensures:
- **Security**: Latest security patches and fixes
- **Features**: Access to new functionality and improvements
- **Compatibility**: Better support for current GitHub features
- **Performance**: Optimizations and efficiency improvements

### Security Note

Actions that were previously pinned to commit SHAs remain pinned to SHAs
(updated to the latest release SHA) to maintain the security benefits of
immutable references.

### Testing

These changes only affect CI/CD workflow configurations and should not
impact application functionality. The workflows should be tested by
running them on a branch before merging.

Signed-off-by: Salman Muin Kayser Chishti <13schishti@gmail.com>

Author: salmanmkc

.github/workflows/deploy-docsite.yml

@@ -55,7 +55,7 @@ jobs:
             - name: Upload Build Artifact
               # Only upload the build artifact when pushed to the main branch
               if: github.event_name == 'push' && github.ref == 'refs/heads/main'
-              uses: actions/upload-pages-artifact@v3
+              uses: actions/upload-pages-artifact@v4
               with:
                   path: docs/build
     deploy: