Bump httplib2 from 0.12.0 to 0.19.0 in /sdks/python

Bumps [httplib2](https://github.com/httplib2/httplib2) from 0.12.0 to 0.19.0.
- [Release notes](https://github.com/httplib2/httplib2/releases)
- [Changelog](https://github.com/httplib2/httplib2/blob/master/CHANGELOG)
- [Commits](httplib2/httplib2@v0.12.0...v0.19.0)

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

sdks/python/container/base_image_requirements.txt

@@ -30,7 +30,7 @@ dill==0.3.1.1
 future==0.18.2
 grpcio==1.32.0
 hdfs==2.5.8
-httplib2==0.12.0
+httplib2==0.19.0
 mock==2.0.0
 oauth2client==4.1.3
 protobuf==3.12.2