Use release-package follow-up PR action

[lukewilliamboswell]

Summary

• update release-package action refs to Add release follow-up PR action roc-lang/release-package#2 while testing the new create-followup-pr action
• replace the direct docs/examples commit push with create-followup-pr
• grant publish-docs pull-requests: write so the action can open/update the follow-up PR

Why

The 1.0.1 release published successfully, but the docs/examples follow-up commit tried to push directly to protected main and was rejected. The shared action moves that GitHub branch/PR mechanic into release-package and avoids direct protected-branch pushes.

Verification

• PASS: Ruby YAML parse for .github/workflows/release.yml and .github/workflows/tests.yaml
• PASS: bash -n scripts/bundle.sh ci/all_tests.sh
• PASS: roc fmt --check examples/csv-movies.roc examples/letters.roc examples/markdown.roc examples/numbers.roc

Notes

• The release-package ref is temporary: 3a25de642bce84c70b0f4ab6b30ee0f730acb5cf from Add release follow-up PR action roc-lang/release-package#2.
• The optional labels input is omitted because this repo does not currently have release/docs labels.