fix(deps): require protobuf<4.0.0 on v1 branch (#1271)

* fix(deps): require protobuf<4.0.0 on v1 branch

* chore: fix ci

Author: parthea

noxfile.py

@@ -206,7 +206,7 @@ def blacken(session):
 def docs(session):
     """Build the docs."""
 
-    session.install("ipython", "recommonmark", "sphinx<3.0.0", "sphinx_rtd_theme")
+    session.install("ipython", "recommonmark", "sphinx<3.0.0", "jinja2<3.1", "sphinx_rtd_theme")
     session.install("google-cloud-storage")
     session.install("-e", ".[all]")
 

setup.py

@@ -34,6 +34,7 @@
     "google-cloud-core >= 1.4.1, < 3.0dev",
     "google-resumable-media >= 0.6.0, < 2.0dev",
     "six >=1.13.0,< 2.0.0dev",
+    "protobuf<4.0.0dev",
 ]
 extras = {
     "bqstorage": [