Add basic GitHub workflows.

This is needed to trigger CI in the PR that adds the new SemanticDB
compiler plugin.

Author: olafurpg

.github/release-drafter.yml

@@ -0,0 +1,4 @@
+template: |
+  ## Pull Requests
+
+  $CHANGES

.github/workflows/release-drafter.yml

@@ -0,0 +1,14 @@
+name: Release Drafter
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  update_release_draft:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: release-drafter/release-drafter@v5
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}