Bump httplib2 from 0.12.1 to 0.19.0

Bumps [httplib2](https://github.com/httplib2/httplib2) from 0.12.1 to 0.19.0.
- [Release notes](https://github.com/httplib2/httplib2/releases)
- [Changelog](https://github.com/httplib2/httplib2/blob/master/CHANGELOG)
- [Commits](httplib2/httplib2@v0.12.1...v0.19.0)

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

requirements.txt

@@ -1,11 +1,12 @@
--i https://pypi.org/simple
-cachetools==3.1.0
+-i https://pypi.org/simple/
+cachetools==4.2.1
 google-api-python-client==1.7.8
-google-auth-httplib2==0.0.3
+google-auth-httplib2==0.0.4
 google-auth==1.6.3
-httplib2==0.12.1
-pyasn1-modules==0.2.4
-pyasn1==0.4.5
-rsa==4.0
-six==1.12.0
-uritemplate==3.0.0
+httplib2==0.19.0
+pyasn1-modules==0.2.8
+pyasn1==0.4.8
+pyparsing==2.4.7
+rsa==4.7
+six==1.15.0
+uritemplate==3.0.1