Add release workflow

.github/workflows/release.yml

@@ -0,0 +1,50 @@
+name: release
+
+on:
+  pull_request_target:
+    types:
+      - closed
+
+permissions:
+  contents: write      # needed for pushing tags/commits & creating releases
+
+jobs:
+  release:
+    # Only run if PR was merged AND has the bump label
+    if: >
+      github.event.pull_request.merged == true &&
+      contains(github.event.pull_request.labels.*.name, 'bump:patch')
+
+    runs-on: ubuntu-latest
+
+    steps:
+      # We check out the BASE branch — this is now the merged code — SAFE
+      - name: Checkout merged code
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.base.ref }}
+          fetch-depth: 0
+
+      # Environment
+      - name: Set up Pixi
+        uses: prefix-dev/setup-pixi@v0.8.9
+
+      # Git identity
+      - name: Set Git identity
+        run: |
+          git config user.name 'github-actions[bot]'
+          git config user.email 'github-actions[bot]@users.noreply.github.com'
+
+      # Bump version
+      - name: Bump version (patch)
+        run: |
+          pixi run bumpver update --patch
+
+      # Create GitHub Release
+      - name: Create Release
+        uses: actions/create-release@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          tag_name: ${{ github.ref_name }}
+          release_name: "Release ${{ github.ref_name }}"