flake8: Ignore build/ directory

Author: tony

setup.cfg

@@ -1,5 +1,5 @@
 [flake8]
-exclude = .*/,.tox,*.egg,qencode/_compat.py,qencode/__*__.py,
+exclude = .*/,.tox,*.egg,build/,qencode/_compat.py,qencode/__*__.py,
 select = E,W,F,N
 max-line-length = 88
 # Stuff we ignore thanks to black: https://github.com/ambv/black/issues/429