Bump urllib3 from 1.26.0 to 1.26.3

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.26.0 to 1.26.3.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/main/CHANGES.rst)
- [Commits](https://github.com/urllib3/urllib3/compare/1.26.0...1.26.3)

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

requirements.txt

@@ -37,6 +37,6 @@ rcssmin==1.0.6
 requests==2.25.1
 rjsmin==1.1.0
 six==1.15.0
-urllib3==1.26.0
+urllib3==1.26.3
 WeRoBot==1.13.1
 Whoosh==2.7.4