Merge pull request #11 from sphinx-doc/tk0miya-patch-1

tox: Fix testenv for python3.10

Author: tk0miya

tox.ini

@@ -8,7 +8,7 @@ python =
     3.7: py37
     3.8: py38
     3.9: py39
-    3.10-dev: py310-dev
+    3.10: py310-dev
 
 [testenv]
 deps=