.gitlab-ci: docs: install the main requirements.txt, treat warnings as errors

.gitlab-ci.yml

@@ -72,9 +72,9 @@ push_docker:
 .docs:
   image: "${CI_REGISTRY_IMAGE}:dev"
   before_script:
-    - pip install -r docs/requirements.txt
+    - pip install -r requirements.txt -r docs/requirements.txt
   script:
-    - (cd docs && make)
+    - (cd docs && SPHINXARGS='-W' make)
     - mv docs/html public
   artifacts:
     paths:

docs/Makefile

@@ -10,7 +10,7 @@ clean:
 	rm -rf html source/cli .buildinfo .doctrees
 
 html:
-	sphinx-build $(buildargs)
+	sphinx-build $(SPHINXARGS) $(buildargs)
 
 serve: html
 	(cd html && python -m http.server 9999)