CI: Use parallel jobs in a matrix for docker-ci

.github/workflows/docker-ci.yml

@@ -7,6 +7,11 @@ env:
 
 jobs:
   main:
+    strategy:
+      fail-fast: false
+      matrix:
+        file: [Dockerfile, Dockerfile.Service]
+
     runs-on: ubuntu-latest
 
     steps:
@@ -18,17 +23,10 @@ jobs:
     - name: Set up Docker Buildx
       uses: docker/setup-buildx-action@v1
 
-    - name: Build Docker image from Dockerfile
+    - name: Build Docker image from ${{ matrix.file }}
       uses: docker/build-push-action@v2
       with:
         context: .
-        platforms: ${{ env.PLATFORMS }}
-        build-args: STEAM_TOKEN_DUMPER_TOKEN=${{ secrets.STEAM_TOKEN_DUMPER_TOKEN }}
-
-    - name: Build Docker image from Dockerfile.Service
-      uses: docker/build-push-action@v2
-      with:
-        context: .
-        file: Dockerfile.Service
+        file: ${{ matrix.file }}
         platforms: ${{ env.PLATFORMS }}
         build-args: STEAM_TOKEN_DUMPER_TOKEN=${{ secrets.STEAM_TOKEN_DUMPER_TOKEN }}