Add GH Action for build workflow

.github/workflows/build.yml

@@ -0,0 +1,61 @@
+name: Build Nginx for Heroku Stacks
+
+on:
+  push:
+    branches:
+      - master
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        target: [heroku-20, heroku-22, heroku-24]
+        arch: [amd64, arm64]
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Run Makefile target
+        run: |
+          if [[ "${{ matrix.target }}" == "heroku-24" || "${{ matrix.arch }}" == "amd64" || "${{ matrix.arch }}" == "arm64" ]]; then
+            make ${{ matrix.target }}-${{ matrix.arch }}
+          else
+            make build-${{ matrix.target }}
+          fi
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v3
+        with:
+          name: |
+            ${{ matrix.target }}${{ (matrix.target == 'heroku-24' && '-' || '') }}${{ matrix.arch }}.tgz
+          path: |
+            nginx-${{ matrix.target }}${{ (matrix.target == 'heroku-24' && '-' || '') }}${{ matrix.arch }}.tgz
+
+
+  commit:
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Download build artifacts
+        uses: actions/download-artifact@v3
+
+      - name: Commit and push artifacts
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          git config --local user.email "[email protected]"
+          git config --local user.name "GitHub Action"
+          mkdir -p builds/
+          mv *.tgz builds/
+          git add builds/*.tgz
+          git commit -m "Add nginx builds for Heroku stacks on multiple architectures"
+          git push