Bump astroid from 2.6.5 to 2.8.0

Bumps [astroid](https://github.com/PyCQA/astroid) from 2.6.5 to 2.8.0.
- [Release notes](https://github.com/PyCQA/astroid/releases)
- [Changelog](https://github.com/PyCQA/astroid/blob/main/ChangeLog)
- [Commits](pylint-dev/astroid@v2.6.5...v2.8.0)

---
updated-dependencies:
- dependency-name: astroid
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

requirements.txt

@@ -1,5 +1,5 @@
 appdirs==1.4.4
-astroid==2.6.5
+astroid==2.8.0
 attrs==21.2.0
 black==21.9b0
 certifi==2021.5.30