build(github): Enable Docker image caching between workflows

For details see [1].

[1]: https://docs.docker.com/build/ci/github-actions/cache/#github-cache

Signed-off-by: Sebastian Schuberth <[email protected]>

.github/workflows/build-and-test.yml

@@ -148,6 +148,33 @@ jobs:
         java-version: 17
     - name: Restore Gradle cache entries
       uses: gradle/gradle-build-action@v2
+    - name: Login to GitHub Container Registry
+      uses: docker/login-action@v2
+      with:
+        registry: ghcr.io
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+    - name: Setup Docker Buildx
+      uses: docker/setup-buildx-action@v2
+    - name: Build and push the Docker image
+      uses: docker/build-push-action@v4
+      with:
+        build-args: USER_ID=1001
+        context: .
+        cache-from: type=registry,ref=ort:buildcache
+        cache-to: type=registry,ref=ort:buildcache,mode=max
+        push: true
+        tags: ort:pr
+    - name: Build and load the Docker image
+      uses: docker/build-push-action@v4
+      with:
+        build-args: USER_ID=1001
+        context: .
+        cache-from: type=registry,ref=ort:buildcache
+        cache-to: type=registry,ref=ort:buildcache,mode=max
+        load: true
+    - name: Build Docker image manually
+      run: DOCKER_BUILDKIT=1 docker build --build-arg USER_ID=1001 .
     - name: Validate Batect wrapper scripts
       uses: batect/batect-wrapper-validation-action@v0
     - name: Run functional tests that do require external tools