Automated releases

[hawk23]

Description

Adds automation using GH actions for the whole release process.

Changes

• Add workflow start-release-train.yml
  • Creates the release branch
  • Bumps the version in all necessary places
  • Does a publish dry-run: dart pub publish --dry-run
  • Test run: https://github.com/bitmovin/bitmovin-player-flutter/actions/runs/7287704111
• Add workflow finish-release-train.yml
  • Adds the release date to CHANGELOG.md
  • Pushes a version tag to trigger the actual publishing of the package (this is a requirement of dart-lang/setup-dart/.github/workflows/publish.yml@v1)
  • Creates a PR to merge release branch, including version tag, back to main
  • Test run: https://github.com/bitmovin/bitmovin-player-flutter/actions/runs/7287786241
• Add workflow publish.yml
  • Based on this guide: https://dart.dev/tools/pub/automated-publishing
  • When a version tag is pushed, publishes the package to pub.dev
  • Creates the according GH release
  • Generates the API doc and uploads it to Bitmovin's CDN
  • Test run: https://github.com/bitmovin/bitmovin-player-flutter/actions/runs/7287788834

Sidenote: The GH release, release branch, merge PR, and tag, that were created by the test run are deleted already again, to have a clean repo state.

Tests

n/a

Checklist (for PR submitters and reviewers)

• 🗒 CHANGELOG.md entry for new/changed features, bug fixes or important code changes: n/a as only internal changes
• 🧪 Tests added and/or updated: n/a
• 📢 New public API is fully documented

[hawk23]

Sneak fix

[hawk23]

To simplify the workflow, the version number and other info is now taken form pubspec.yaml. One less version to bump