build(deps): update distro requirement from ==1.8.* to ==1.9.*

Updates the requirements on [distro](https://github.com/python-distro/distro) to permit the latest version.
- [Release notes](https://github.com/python-distro/distro/releases)
- [Changelog](https://github.com/python-distro/distro/blob/master/CHANGELOG.md)
- [Commits](python-distro/distro@v1.8.0...v1.9.0)

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

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

requirements/base.txt

@@ -1,4 +1,4 @@
-distro==1.8.* ; sys_platform == 'linux'
+distro==1.9.* ; sys_platform == 'linux'
 dulwich>=0.21.5,<0.21.7
 giturlparse>=0.10,<0.13
 imagesize>=1.4,<1.5