ci: bump peter-evans/create-pull-request from 6 to 8

Bumps [peter-evans/create-pull-request](https://github.com/peter-evans/create-pull-request) from 6 to 8.
- [Release notes](https://github.com/peter-evans/create-pull-request/releases)
- [Commits](peter-evans/create-pull-request@v6...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>

Author: dependabot[bot]

.github/workflows/generate-command.yml

@@ -227,7 +227,7 @@ jobs:
             - name: Create Pull Request
               if: ${{ !inputs.dry_run && steps.changes.outputs.has_changes == 'true' && github.event.inputs.pr == '' }}
               id: create-pr
-              uses: peter-evans/create-pull-request@v6
+              uses: peter-evans/create-pull-request@v8
               with:
                   token: ${{ steps.app-token.outputs.token }}
                   commit-message: "chore: regenerate SDK with Speakeasy"