Add tags for releases (#4524)

## Problem

It's not a trivial task to find corresponding changes for a particular
release (for example, for 3371 — 🤷)

Ref:
https://neondb.slack.com/archives/C04BLQ4LW7K/p1686761537607649?thread_ts=1686736854.174559&cid=C04BLQ4LW7K

## Summary of changes
- Tag releases
- Add a manual trigger for the release workflow

.github/workflows/build_and_test.yml

@@ -914,6 +914,20 @@ jobs:
             exit 1
           fi
 
+      - name: Create tag "release-${{ needs.tag.outputs.build-tag }}"
+        if: github.ref_name == 'release'
+        uses: actions/github-script@v6
+        with:
+          # Retry script for 5XX server errors: https://github.com/actions/github-script#retries
+          retries: 5
+          script: |
+            github.rest.git.createRef({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              ref: "refs/tags/release-${{ needs.tag.outputs.build-tag }}",
+              sha: context.sha,
+            })
+
   promote-compatibility-data:
     runs-on: [ self-hosted, gen3, small ]
     container:

.github/workflows/release.yml

@@ -3,6 +3,7 @@ name: Create Release Branch
 on:
   schedule:
     - cron: '0 10 * * 2'
+  workflow_dispatch:
 
 jobs:
   create_release_branch: