Pin ubuntu version for github workflow to 20.04

Author: pitbulk

.github/workflows/python-package.yml

@@ -7,7 +7,7 @@ on: [push, pull_request]
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
 
     steps:
     - uses: actions/checkout@v2
@@ -27,5 +27,6 @@ jobs:
       run: |
         coverage run --source=src/onelogin/saml2 --rcfile=tests/coverage.rc setup.py test
         coverage report -m --rcfile=tests/coverage.rc
-        pycodestyle tests/src/OneLogin/saml2_tests/*.py demo-flask/*.py demo-django/*.py src/onelogin/saml2/*.py --config=tests/pep8.rc
-        pyflakes src/onelogin/saml2 demo-django demo-flask tests/src/OneLogin/saml2_tests
+        #pycodestyle tests/src/OneLogin/saml2_tests/*.py demo-flask/*.py demo-django/*.py src/onelogin/saml2/*.py --config=tests/pep8.rc
+        #pyflakes src/onelogin/saml2 demo-django demo-flask tests/src/OneLogin/saml2_tests
+        flake8 --ignore E226,E302,E41,E731,E501,C901,W504