Don't check generated pxi files

Author: xhochy

.flake8.cython-header

@@ -1,4 +1,4 @@
 [flake8]
-filename = *.pxd,*.pxi,*.pxi.in
+filename = *.pxd,*.pxi.in
 select = E501,E302,E203,E111,E114,E221,E303,E231,E126,F403