ci: Streamline Gitflow release process (#7113)

Author: mydea

.github/workflows/auto-release.yml

@@ -0,0 +1,38 @@
+name: Gitflow - Auto prepare release
+on:
+  pull_request:
+    types:
+      - closed
+    branches:
+      - master
+
+# This workflow tirggers a release when merging a branch with the pattern `prepare-release/VERSION` into master.
+jobs:
+  release:
+    runs-on: ubuntu-20.04
+    name: 'Prepare a new version'
+
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          token: ${{ secrets.GH_RELEASE_PAT }}
+          fetch-depth: 0
+
+      # https://github.com/actions-ecosystem/action-regex-match
+      - uses: actions-ecosystem/action-regex-match@v2
+        id: version
+        with:
+          # Parse version from head branch
+          text: ${{ github.head_ref }}
+          # match: refs/heads/preprare-release/xx.xx.xx
+          regex: '^refs\/heads\/preprare-release\/(\d+\.\d+\.\d+)$'
+
+      - name: Prepare release
+        uses: getsentry/action-prepare-release@v1
+        if: github.event.pull_request.merged == true && steps.version.outputs.match != ''
+        env:
+          GITHUB_TOKEN: ${{ secrets.GH_RELEASE_PAT }}
+        with:
+          version: ${{ steps.version.outputs.match != '' }}
+          force: false
+          merge_target: master

.github/workflows/build.yml

@@ -137,7 +137,8 @@ jobs:
       # Note: These next three have to be checked as strings ('true'/'false')!
       is_develop: ${{ github.ref == 'refs/heads/develop' }}
       is_release: ${{ startsWith(github.ref, 'refs/heads/release/') }}
-      is_gitflow_sync: ${{ github.head_ref == 'refs/heads/develop' || github.head_ref == 'refs/heads/master' }}
+      # When merging into master, or from master
+      is_gitflow_sync: ${{ github.head_ref == 'refs/heads/master' || github.ref == 'refs/heads/master' }}
       has_gitflow_label:
         ${{ github.event_name == 'pull_request' && contains(steps.pr-labels.outputs.labels, ' Gitflow ') }}
       force_skip_cache:

.github/workflows/gitflow-sync-master.yml

@@ -6,20 +6,20 @@ _These steps are only relevant to Sentry employees when preparing and publishing
 **If you want to release a new SDK for the first time, be sure to follow the [New SDK Release Checklist](./new-sdk-release-checklist.md)**
 
 1. Determine what version will be released (we use [semver](https://semver.org)).
-2. Update [`CHANGELOG.md`](https://github.com/getsentry/sentry-javascript/edit/master/CHANGELOG.md) to add an entry for the next release number and a list of changes since the last release. (See details below.)
-  a. Merging the Changelog PR will automatically trigger a sync from `develop` -> `master`
-3. Run the [Prepare Release](https://github.com/getsentry/sentry-javascript/actions/workflows/release.yml) workflow.
-  a. Wait for this until the sync to `master` is completed.
-4. A new issue should appear in https://github.com/getsentry/publish/issues.
-5. Ask a member of the [@getsentry/releases team](https://github.com/orgs/getsentry/teams/releases/members) to approve the release.
+2. Create a branch `prepare-release/VERSION`, eg. `prepare-release/7.37.0`, off develop
+3. Update [`CHANGELOG.md`](https://github.com/getsentry/sentry-javascript/edit/master/CHANGELOG.md) to add an entry for the next release number and a list of changes since the last release. (See details below.)
+4. Create a PR towards `master` branch
+5. When the PR is merged, it will automatically trigger the [Prepare Release](https://github.com/getsentry/sentry-javascript/actions/workflows/release.yml) on master.
+6. A new issue should appear in https://github.com/getsentry/publish/issues.
+7. Ask a member of the [@getsentry/releases team](https://github.com/orgs/getsentry/teams/releases/members) to approve the release.
   a. Once the release is completed, a sync from `master` ->` develop` will be automatically triggered
 
 ## Updating the Changelog
 
-1. Create a new branch.
+1. Create a new branch `prepare-release/VERSION` off of `develop`, e.g. `prepare-release/7.37.1`.
 2. Run `yarn changelog` and copy everything
 3. Create a new section in the changelog, deciding based on the changes whether it should be a minor bump or a patch release.
 4. Paste in the logs you copied earlier.
 5. Delete any which aren't user-facing changes.
 7. If any of the PRs are from external contributors, include underneath the commits `Work in this release contributed by <list of external contributors' GitHub usernames>. Thank you for your contributions!`. If there's only one external PR, don't forget to remove the final `s`. If there are three or more, use an Oxford comma. (It's in the Sentry styleguide!)
-8. Commit, push, and open a PR with the title `meta: Update changelog for <fill in relevant version here>` against `develop` branch.
+8. Commit, push, and open a PR with the title `meta(changelog): Update changelog for VERSION` against `master` branch.