Create GitHub release from release tag (#5246)

## Problem

This PR creates a GitHub release from a release tag with an
autogenerated changelog: https://github.com/neondatabase/neon/releases

## Summary of changes
- Call GitHub API to create a release

.github/workflows/build_and_test.yml

@@ -1081,13 +1081,27 @@ jobs:
           # Retry script for 5XX server errors: https://github.com/actions/github-script#retries
           retries: 5
           script: |
-            github.rest.git.createRef({
+            await github.rest.git.createRef({
               owner: context.repo.owner,
               repo: context.repo.repo,
               ref: "refs/tags/${{ needs.tag.outputs.build-tag }}",
               sha: context.sha,
             })
 
+      - name: Create GitHub release
+        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: |
+            await github.rest.repos.createRelease({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              tag_name: "${{ needs.tag.outputs.build-tag }}",
+              generate_release_notes: true,
+            })
+
   promote-compatibility-data:
     needs: [ check-permissions, promote-images, tag, regress-tests ]
     if: github.ref_name == 'release'