Fix default tolerance

Author: astrofrog

tests/test_pytest_mpl.py

@@ -23,7 +23,7 @@
 WIN = sys.platform.startswith('win')
 
 # In some cases, the fonts on Windows can be quite different
-DEFAULT_TOLERANCE = 10 if WIN else None
+DEFAULT_TOLERANCE = 10 if WIN else 2
 
 
 @pytest.mark.mpl_image_compare(baseline_dir=baseline_dir_local,