build(deps): update dulwich requirement

Updates the requirements on [dulwich](https://github.com/dulwich/dulwich) to permit the latest version.
- [Release notes](https://github.com/dulwich/dulwich/releases)
- [Changelog](https://github.com/jelmer/dulwich/blob/master/NEWS)
- [Commits](jelmer/dulwich@dulwich-0.21.7...dulwich-0.22.6)

---
updated-dependencies:
- dependency-name: dulwich
  dependency-type: direct:production
...

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

requirements/base.txt

@@ -1,5 +1,5 @@
 distro==1.9.* ; sys_platform == 'linux'
-dulwich>=0.21.7,<0.22.5
+dulwich>=0.21.7,<0.22.7
 giturlparse>=0.12,<0.13
 imagesize>=1.4,<1.5
 packaging>=20,<25