fix: Docker Image push to GitHub Container Registry

[maximearmstrong]

Fixes #1105 : Docker builds are failing

This PR replaces the Personal Access Token (PAT) used in the docker.yml workflow with a GitHub Token. According to GitHub, PATs used to authenticate to ghcr.io should be avoided.

Along with the changes made in this PR, the steps shown here were followed so that the package could access the GitHub token.

Expected behavior:

The Docker Image push to GitHub Container Registry should work properly.

Explain and/or show screenshots for how you expect the pull request to work in your testing (in case other devices exhibit different behavior).

Please make sure these boxes are checked before submitting your pull request - thanks!

• Run the unit tests with gradle test to make sure you didn't break anything
• Format the title like "feat: [new feature short description]". Title must follow the Conventional Commit Specification(https://www.conventionalcommits.org/en/v1.0.0/).
• Linked all relevant issues
• Include screenshot(s) showing how this pull request works and fixes the issue(s)

[barbeau]

Thanks @maximearmstrong! We can confirm this works after merge to main branch.

[github-actions]

Thank you for this contribution! 🍰✨🦄

Information about source corruption

0 out of 1248 sources are corrupted.

Acceptance test details

The changes in this pull request did not trigger any new errors on known GTFS datasets from the MobilityDatabase.
Download the full acceptance test report for commit 35dfcd1 here (report will disappear after 90 days).

[maximearmstrong]

Thanks @maximearmstrong! We can confirm this works after merge to main branch.

It worked! 🚀