Bump distlib from 0.3.0 to 0.3.1

Bumps [distlib](https://bitbucket.org/pypa/distlib) from 0.3.0 to 0.3.1.
- [Changelog](https://bitbucket.org/pypa/distlib/src/master/CHANGES.rst)
- [Commits](https://bitbucket.org/pypa/distlib/branches/compare/0.3.1..0.3.0)

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

requirements-indirect.txt

@@ -4,7 +4,7 @@ attrs==19.3.0
 bcrypt==3.1.7
 cffi==1.14.0
 cryptography==2.9.2
-distlib==0.3.0
+distlib==0.3.1
 entrypoints==0.3
 filelock==3.0.12
 gitdb2==4.0.2