Update dependency google-auth-httplib2 to v0.0.4 [(#4255)](GoogleCloudPlatform/python-docs-samples#4255)

Co-authored-by: Takashi Matsuo <tmatsuo@google.com>

Author: 2 people

packages/google-cloud-language/samples/snippets/api/requirements.txt

@@ -1,3 +1,3 @@
 google-api-python-client==1.9.3
 google-auth==1.18.0
-google-auth-httplib2==0.0.3
+google-auth-httplib2==0.0.4