Fix broken make pylint (#66)

We now stop if any linting fails thereby failing the job if any fail.
Previously the exit code for the job would be "0" if the last linting
succeeded.

Fixes #65

Makefile

@@ -26,7 +26,7 @@ push: build
 pylint: build $(PYTHON_COMMANDS)
 	$(foreach file, $(notdir $(PYTHON_COMMANDS)), \
 		echo "Linting $(file)"; \
-		docker run --entrypoint pylint --rm "ghcr.io/${IMAGE}:latest" /commands/$(file); \
+		docker run --entrypoint pylint --rm "ghcr.io/${IMAGE}:latest" /commands/$(file) || exit 1; \
 	)
 
 .PHONY: push