build(deps): bump dnspython from 2.4.0 to 2.6.1 in /src

Bumps [dnspython](https://github.com/rthalley/dnspython) from 2.4.0 to 2.6.1.
- [Release notes](https://github.com/rthalley/dnspython/releases)
- [Changelog](https://github.com/rthalley/dnspython/blob/main/doc/whatsnew.rst)
- [Commits](rthalley/dnspython@v2.4.0...v2.6.1)

---
updated-dependencies:
- dependency-name: dnspython
  dependency-type: indirect
...

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