tox: Run flake8 on 'docs' too

There's only one Python file here but it's an easy addition.

Signed-off-by: Stephen Finucane <[email protected]>

Author: stephenfin

docs/conf.py

@@ -5,7 +5,7 @@
 import git_pw
 
 try:
-    import sphinx_rtd_theme
+    import sphinx_rtd_theme  # noqa
     has_rtd_theme = True
 except ImportError:
     has_rtd_theme = False

tox.ini

@@ -15,7 +15,7 @@ skip_install = true
 deps =
   flake8
 commands =
-  flake8 {posargs:git_pw tests}
+  flake8 {posargs:git_pw tests docs}
 
 [testenv:mypy]
 deps=