Bump dnspython from 2.2.1 to 2.4.2

Bumps [dnspython](https://github.com/rthalley/dnspython) from 2.2.1 to 2.4.2.
- [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/v2.2.1...v2.4.2)

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

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

pyproject.toml

@@ -35,7 +35,7 @@ click-repl = "==0.3.0"
 colorama = "==0.4.4"
 defusedxml = "==0.7.1"
 deprecated = "==1.2.14"
-dnspython = "==2.2.1"
+dnspython = "==2.4.2"
 docopt = "==0.6.2"
 docutils = "==0.16"
 eventlet = "==0.33.3"