Automatically create a release when version changes in CMakeLists

.github/workflows/ubuntu.yml

@@ -56,7 +56,7 @@ jobs:
           cmake .. -DWITH_VIDEO_DECODING=On -DWITH_VIDEO_DEVICE=On -DWITH_OPENSLIDE_SUPPORT=On -DWITH_STB_IMAGE=On -DWITH_LIBSIXEL=On
           make -k
 
-  AppImage:
+  AppImageBuild:
     runs-on: ubuntu-latest
     name: Build AppImage
     steps:
@@ -118,8 +118,6 @@ jobs:
           name: timg-${{ env.PACKAGE_VERSION }}-x86_64.AppImage
           path: timg-${{ env.PACKAGE_VERSION }}-x86_64.AppImage
 
-      # TODO: upload to release
-
   CodeFormatting:
     if: false   # currently, there is no clang-format-13 in ubuntu latest
     runs-on: ubuntu-latest
@@ -137,3 +135,51 @@ jobs:
 
     - name: Run formatting style check
       run: ./.github/bin/run-clang-format.sh
+
+  TagAndRelease:
+    needs: [ AppImage ]
+    name: Version Tagging
+    runs-on: ubuntu-latest
+    #if: ${{github.event_name == 'push' && github.ref == 'refs/heads/main'}}
+    permissions:
+      contents: write
+
+    steps:
+    - name: 📥 Download artifacts
+      uses: actions/download-artifact@v3
+
+    - uses: actions/checkout@v3
+      with:
+       fetch-depth: 0
+       token: ${{ secrets.GITHUB_TOKEN }}
+
+    - name: Tag with CMake version if not already.
+      run: |
+        git config --local user.name "Development Bot"
+        git config --local user.email "[email protected]"
+
+        # We want to tag whenever the cmake version changes. So extract the
+        # hash of when the current version was entered.
+        read TAG_HASH TAG_VERSION <<<$(git annotate -l CMakeLists.txt | sed 's/\(^[0-9A-Fa-f]\+\).*project(timg VERSION \([0-9]\+\.[0-9]\+\.[0-9]\+\).*/\1 \2/p;d')
+
+        echo "timg Version v${TAG_VERSION} at hash ${TAG_HASH}"
+
+        # If this is the first time we see this tag: apply.
+        if [ -z "$(git tag -l "v${TAG_VERSION}")" ]; then
+          git tag -a "v${TAG_VERSION}" ${TAG_HASH} -m "Update to v${TAG_VERSION}"
+          git push origin "v${TAG_VERSION}"
+          echo "RELEASE_TAG=v${TAG_VERSION}" >> $GITHUB_ENV
+        else
+          echo "Tag does exist already"
+        fi
+
+    - name: 🎉 Release If Tagged
+      if ${{ env.RELEASE_TAG != '' }}
+      uses: svenstaro/upload-release-action@v2
+      with:
+        repo_token: ${{ secrets.GITHUB_TOKEN }}
+        file: artifact/timg-*.AppImage
+        tag: ${{ env.RELEASE_TAG }}
+        overwrite: true
+        file_glob: true
+        prerelease: true