Bump pycodestyle from 2.6.0 to 2.7.0

Bumps [pycodestyle](https://github.com/PyCQA/pycodestyle) from 2.6.0 to 2.7.0.
- [Release notes](https://github.com/PyCQA/pycodestyle/releases)
- [Changelog](https://github.com/PyCQA/pycodestyle/blob/master/CHANGES.txt)
- [Commits](https://github.com/PyCQA/pycodestyle/compare/2.6.0...2.7.0)

Signed-off-by: dependabot[bot] <support@github.com>

requirements-dev.txt

@@ -1,7 +1,7 @@
 mock==4.0.3
 nose2[coverage_plugin]==0.10.0
 cov-core==1.15.0
-pycodestyle==2.6.0
+pycodestyle==2.7.0
 pylint==2.7.4
 splinter==0.14.0
 transifex-client==0.14.2