Force coloured output in build.

.drone.yml

@@ -45,7 +45,7 @@ steps:
     image: deukhoofd/linux64builder
     failure: ignore
     commands:
-      - run-clang-format.py -r src/ CInterface/ tests/
+      - run-clang-format.py -r src/ CInterface/ tests/ --color=always
   - name: test-release-windows
     image: deukhoofd/windowsbuilder
     volumes: