Bump distlib from 0.3.6 to 0.3.8 in /src

Bumps [distlib](https://github.com/pypa/distlib) from 0.3.6 to 0.3.8.
- [Release notes](https://github.com/pypa/distlib/releases)
- [Changelog](https://github.com/pypa/distlib/blob/master/CHANGES.rst)
- [Commits](pypa/distlib@0.3.6...0.3.8)

---
updated-dependencies:
- dependency-name: distlib
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

src/requirements.txt

@@ -22,7 +22,7 @@ dill==0.3.6
     # via
     #   -r src/requirements.txt
     #   pylint
-distlib==0.3.6
+distlib==0.3.8
     # via
     #   -r src/requirements.txt
     #   virtualenv