Bump flake8-isort from 2.5 to 2.6.0

Bumps [flake8-isort](https://github.com/gforcada/flake8-isort) from 2.5 to 2.6.0.
- [Release notes](https://github.com/gforcada/flake8-isort/releases)
- [Changelog](https://github.com/gforcada/flake8-isort/blob/master/CHANGES.rst)
- [Commits](gforcada/flake8-isort@2.5...2.6.0)

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

Pipfile

@@ -15,7 +15,7 @@ selenium = "==3.141.0"
 coveralls = "==1.5.1"
 flake8 = "==3.6.0"
 flake8-docstrings = "==1.3.0"
-flake8-isort = "==2.5"
+flake8-isort = "==2.6.0"
 pytest = "==3.10.1"
 pytest-cov = "==2.6.0"
 pytest-selenium = "==1.14.0"