Makefile: docs: use tox

Author: blueyed

Makefile

@@ -17,11 +17,8 @@ $(VENV)/bin/pytest: $(VENV)/bin/python requirements.txt
 	$(VENV)/bin/pip install -Ur requirements.txt
 	touch $@
 
-$(VENV)/bin/sphinx-build: $(VENV)/bin/pip
-	$(VENV)/bin/pip install sphinx
-
-docs: $(VENV)/bin/sphinx-build
-	SPHINXBUILD=../$(VENV)/bin/sphinx-build $(MAKE) -C docs html
+docs:
+	tox -e docs
 
 # See setup.cfg for configuration.
 isort: