Merge branch 'dependabot/pip/black-20.8b1' of github.com:realpython/materials into dependabot/pip/black-20.8b1

Author: dbader

concurrency-overview/requirements.txt

@@ -8,7 +8,6 @@ attrs==18.1.0
 certifi==2018.8.13
 chardet==3.0.4
 contextvars==2.3
-flake8==3.5.0
 h11==0.8.1
 idna==2.7
 immutables==0.6
@@ -23,8 +22,6 @@ pathlib2==2.3.2
 pluggy==0.7.1
 py==1.6.0
 pycodestyle==2.3.1
-pyflakes==1.6.0
-pylint==2.1.1
 pytest==3.7.3
 requests==2.19.1
 six==1.11.0

requirements.txt

@@ -1,2 +1,2 @@
 black==20.8b1
-flake8==3.8.2 
+flake8==3.8.4