Add Github workflow for building linux binary and and uploading artifact if #linux-build is specified in commit message

.github/workflows/linux-build.yml

@@ -0,0 +1,46 @@
+name: Build only Linux binary
+
+on: push
+
+jobs:
+  release:
+    runs-on: ${{ matrix.os }}
+    if: ${{ contains(github.event.head_commit.message, '#linux-build') }}
+
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+
+    steps:
+      - name: Check out Git repository
+        uses: actions/checkout@v1
+
+      - name: Install Node.js, NPM and Yarn
+        uses: actions/setup-node@v1
+        with:
+          node-version: 18
+
+      - name: Build/release Electron app
+        uses: samuelmeuli/action-electron-builder@v1
+        with:
+          # Specify electron-builder config file
+          args: -c electron-builder.json5
+
+          # NPM script to execute before electron-builder
+          build_script_name: prebuild
+
+          # GitHub token, automatically provided to the action
+          # (No need to define this secret in the repo settings)
+          github_token: ${{ secrets.github_token }}
+
+          # If the commit is tagged with a version (e.g. "v1.0.0"),
+          # release the app after building
+          release: ${{ startsWith(github.ref, 'refs/tags/v') }}
+      
+      - name: Upload Linux artifact
+        if: ${{ matrix.os == 'ubuntu-latest' }}
+        uses: actions/upload-artifact@v3
+        with:
+          name: heynote-linux-${{ github.sha }}
+          path: release/*/Heynote_*.AppImage
+          retention-days: 30