Publish checklist

This is just a cheat sheet for me when I publish a new library version for the following library folders:

flutter_floating_map_marker_titles_core
flutter_map_floating_marker_titles
google_maps_flutter_floating_marker_titles

These steps are based on the official documentation.

Publishing steps:

Update the version in pubspec.yaml
Update the changelog file CHANGELOG.md documenting the changes of that new version
Test the publishing with this command: flutter pub publish --dry-run
Actually publish with this command: flutter pub publish