Bump dnspython from 1.16.0 to 2.2.1

Bumps [dnspython](https://github.com/rthalley/dnspython) from 1.16.0 to 2.2.1.
- [Release notes](https://github.com/rthalley/dnspython/releases)
- [Changelog](https://github.com/rthalley/dnspython/blob/master/doc/whatsnew.rst)
- [Commits](https://github.com/rthalley/dnspython/compare/v1.16.0...v2.2.1)

---
updated-dependencies:
- dependency-name: dnspython
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

requirements.txt

@@ -5,7 +5,7 @@ cffi==1.14.5
 chardet==3.0.4
 click==7.1.2
 cssselect==1.1.0
-dnspython==1.16.0
+dnspython==2.2.1
 docker==4.4.1
 feedparser==6.0.8
 gitdb==4.0.9