Bump httplib2 from 0.18.1 to 0.19.0

Bumps [httplib2](https://github.com/httplib2/httplib2) from 0.18.1 to 0.19.0.
- [Release notes](https://github.com/httplib2/httplib2/releases)
- [Changelog](https://github.com/httplib2/httplib2/blob/master/CHANGELOG)
- [Commits](httplib2/httplib2@v0.18.1...v0.19.0)

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

requirements.txt

@@ -50,7 +50,7 @@ googleapis-common-protos==1.52.0
 grandalf==0.6
 grpcio==1.28.1
 h5py==2.10.0
-httplib2==0.18.1
+httplib2==0.19.0
 idna==2.6
 importlib-metadata==1.7.0
 ipykernel==5.3.4