Update 'create-pr' action in release workflow to latest (microsoft#5415)

A [warning is
shown](https://github.com/microsoft/DeepSpeed/actions/runs/8695213322/job/23845782048#step:10:31)
when we do releases:

```
[deploy](https://github.com/microsoft/DeepSpeed/actions/runs/8695213322/job/23845782048)
Node.js 16 actions are deprecated. Please update the following actions to use Node.js 20: peter-evans/create-pull-request@v4. For more information see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/.
```

To resolve this we update the create a pull request to `@v6`, see
release notes
[here](https://github.com/peter-evans/create-pull-request/releases)

.github/workflows/release.yml

@@ -35,7 +35,7 @@ jobs:
       run: |
         python release/bump_patch_version.py --current_version ${{ env.RELEASE_VERSION }}
     - name: Create Pull Request
-      uses: peter-evans/create-pull-request@v4
+      uses: peter-evans/create-pull-request@v6
       with:
         token: ${{ secrets.GH_PAT }}
         add-paths: |