Add support for automatic Pull Request creation in update-gradle-wrapper action

[warting]

No description provided.

[Copilot]

Pull request overview

This PR adds support for automatic Pull Request creation to the update-gradle-wrapper action, allowing it to commit and create PRs with Gradle wrapper updates automatically when configured.

Key changes:

• Adds create-pr and token inputs to enable optional automatic PR creation
• Adds gradle-version output to expose the resolved Gradle version (useful for PR titles/branches)
• Updates the wrapper update process to run gradlew wrapper twice to ensure all files are properly regenerated
• Updates test workflow to use the new PR creation feature with GitHub App token

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
update-gradle-wrapper/update-gradle-wrapper.sh	Adds double wrapper execution for complete file regeneration and outputs the resolved gradle-version
update-gradle-wrapper/action.yml	Adds create-pr and token inputs, gradle-version output, and integrates peter-evans/create-pull-request action
update-gradle-wrapper/README.md	Adds comprehensive documentation for the new PR creation feature with examples and updated requirements
.github/workflows/test-update-gradle-wrapper.yml	Updates test workflow to demonstrate PR creation feature with GitHub App token authentication

[Copilot]

The workflow file should use 'on': (with quotes) instead of on: to be consistent with the repository's YAML style convention. Other workflow files in this repository (test.yml, test-shell.yml, and release.yml) all use the quoted format 'on': to avoid yamllint truthy warnings.

Suggested change

	on:
	'on':