Bump peter-evans/create-pull-request from 4 to 6

Bumps [peter-evans/create-pull-request](https://github.com/peter-evans/create-pull-request) from 4 to 6.
- [Release notes](https://github.com/peter-evans/create-pull-request/releases)
- [Commits](peter-evans/create-pull-request@v4...v6)

---
updated-dependencies:
- dependency-name: peter-evans/create-pull-request
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/on-push-do-doco.yml

@@ -22,7 +22,7 @@ jobs:
           --toc-level 5
       shell: bash
     - name: Create Pull Request
-      uses: peter-evans/create-pull-request@v4
+      uses: peter-evans/create-pull-request@v6
       with:
         branch: bot/action-doc-toc
         commit-message: "[docs] Regenerate tables of contents"