chore: create release automation script

[reidzeibel]

Trying to create automation script for release, at least from what I tested, it seems working as intended, although I haven't really tried publishing a version actually, just in case it breaks something (like maybe entur version registration stuff) 😨 .

Please let me know if there are stuff to improve.

UPDATE
Script now can be run using yarn release

If triggered on Master: do a new version release with RC1
If triggered on Release: do a new RC release, if no release yet, do RC1

Otherwise here's what the script will do:

• Automatically creates the release branch if it is not there yet
• Automatically creates and publishes the release
• Creates a PR for bumping the version number
• register the new version with Entur

OLD VERSION

The script can be run by calling: `./release.sh {VERSION-RC}`, for example `./release.sh 1.79-rc1`

Then it will:

• Create release branch, checkout that branch
• create and publish release draft with the version we provided
• bump version number
• register with entur
• make a PR to master for bumping the version number.

The only manual thing we need to do is to approve and merge the version bump PR since the master branch is protected and PRs require approval before merging.

[tormoseng]

@reidzeibel Will the script handle if you've already created the release branch manually from before? In many cases we create a release branch, but not the candidate for different reasons.

EDIT: Sorry.

else
  echo "Existing major version. Checking out '$RELEASE_BRANCH'."
  git checkout "$RELEASE_BRANCH"
  git pull origin "$RELEASE_BRANCH"
  echo "Successfully checked out and updated '$RELEASE_BRANCH'."