Add flake8 config

While I don't intend to check this automatically, it's nice to have this
config to avoid clashes with Black.

Author: meshy

.flake8

@@ -0,0 +1,7 @@
+[flake8]
+exclude = .direnv, .env, .venv, venv
+ignore =
+    E203  # whitespace before ':' (conflicts with Black)
+    E501  # line too long (probably right, but if Black let it go, Flake8 should too)
+    W503  # line break before binary operator (conflicts with Black)
+max_line_length = 88