Requirements: Remove flake8-debugger

__pip install flake8-debugger__ fails on Python 3

requirements/dev.txt

@@ -9,7 +9,7 @@ factory-boy==2.8.1
 # Lint and code style
 flake8==3.6.0
 flake8-blind-except==0.1.1
-flake8-debugger==3.1.0
+# flake8-debugger==3.1.0
 flake8-docstrings==1.3.0
 flake8-isort==2.5
 flake8-quotes==1.0.0