build(deps): bump peter-evans/create-pull-request from 5 to 8

Bumps [peter-evans/create-pull-request](https://github.com/peter-evans/create-pull-request) from 5 to 8.
- [Release notes](https://github.com/peter-evans/create-pull-request/releases)
- [Commits](https://github.com/peter-evans/create-pull-request/compare/v5...v8)

---
updated-dependencies:
- dependency-name: peter-evans/create-pull-request
  dependency-version: '8'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/update-flakes.yml

@@ -16,7 +16,7 @@ jobs:
     - name: Update flake inputs
       run: nix flake update
     - name: Create Pull Request
-      uses: peter-evans/create-pull-request@v5
+      uses: peter-evans/create-pull-request@v8
       with:
         commit-message: "flake.lock: Update"
         title: "Update flake inputs"