CI: Enable build also for debug configuration

With more and more conditionals depending on the configuration it starts making sense to build and test also debug build (it was broken for a short while)

.github/workflows/docker-ci.yml

@@ -10,6 +10,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
+        configuration: [Debug, Release]
         file: [Dockerfile, Dockerfile.Service]
 
     runs-on: ubuntu-latest
@@ -23,10 +24,12 @@ jobs:
     - name: Set up Docker Buildx
       uses: docker/setup-buildx-action@v1.5.1
 
-    - name: Build Docker image from ${{ matrix.file }}
+    - name: Build ${{ matrix.configuration }} Docker image from ${{ matrix.file }}
       uses: docker/build-push-action@v2.6.1
       with:
         context: .
         file: ${{ matrix.file }}
         platforms: ${{ env.PLATFORMS }}
-        build-args: STEAM_TOKEN_DUMPER_TOKEN=${{ secrets.STEAM_TOKEN_DUMPER_TOKEN }}
+        build-args: |
+          CONFIGURATION=${{ matrix.configuration }}
+          STEAM_TOKEN_DUMPER_TOKEN=${{ secrets.STEAM_TOKEN_DUMPER_TOKEN }}