add flake8 config

.flake8

@@ -0,0 +1,12 @@
+[flake8]
+ignore = E501, E302
+exclude =
+    # No need to traverse our git directory
+    .git,
+    # There's no value in checking cache directories
+    __pycache__,
+    # The conf file is mostly autogenerated, ignore it
+    docs/source/conf.py,
+    # This contains our built documentation
+    build,
+max-complexity = 10