refactor: remove duplication in build arguments

docker-compose.yaml

@@ -1,8 +1,11 @@
+x-build-args: &default-build-args
+  context: .
+  dockerfile: tools/docker/images/Dockerfile
+
 services:
   app:
     build:
-      context: .
-      dockerfile: tools/docker/images/Dockerfile
+      <<: *default-build-args
       target: app
     command: generate --port "${SCULPIN_PORT:-80}" --url "${SCULPIN_URL:-http://localhost}" --env "${SCULPIN_ENV:-dev}" "${SCULPIN_GENERATE_ARGS}"
     volumes:
@@ -18,8 +21,7 @@ services:
 
   assets:
     build:
-      context: .
-      dockerfile: tools/docker/images/Dockerfile
+      <<: *default-build-args
       target: assets
     volumes:
       - assets:/node/source/build