fix(deps): require protobuf<4.0.0 on v1 branch (#448)

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

* chore: fix ci

* chore: fix ci

noxfile.py

@@ -26,10 +26,13 @@
 BLACK_VERSION = "black==19.3b0"
 BLACK_PATHS = ["docs", "google", "tests", "noxfile.py", "setup.py"]
 
-DEFAULT_PYTHON_VERSION = "3.7"
+DEFAULT_PYTHON_VERSION = "3.8"
 SYSTEM_TEST_PYTHON_VERSIONS = ["2.7", "3.7"]
 UNIT_TEST_PYTHON_VERSIONS = ["2.7", "3.5", "3.6", "3.7", "3.8"]
 
+# Error if a python version is missing
+nox.options.error_on_missing_interpreters = True
+
 
 @nox.session(python=DEFAULT_PYTHON_VERSION)
 def lint(session):
@@ -38,7 +41,7 @@ def lint(session):
     Returns a failure if the linters find linting errors or sufficiently
     serious code quality issues.
     """
-    session.install("flake8", BLACK_VERSION)
+    session.install("flake8", BLACK_VERSION, "click<8.1")
     session.run("black", "--check", *BLACK_PATHS)
     session.run("flake8", "google", "tests")
 
@@ -53,7 +56,7 @@ def blacken(session):
     That run uses an image that doesn't have 3.6 installed. Before updating this
     check the state of the `gcp_ubuntu_config` we use for that Kokoro run.
     """
-    session.install(BLACK_VERSION)
+    session.install(BLACK_VERSION, "click<8.1")
     session.run("black", *BLACK_PATHS)
 
 

setup.py

@@ -29,7 +29,8 @@
 # 'Development Status :: 5 - Production/Stable'
 release_status = "Development Status :: 5 - Production/Stable"
 dependencies = [
-    "google-api-core[grpc] >= 1.31.5, <3.0.0dev,!=2.0.*,!=2.1.*,!=2.2.*,!=2.3.0"
+    "google-api-core[grpc] >= 1.31.5, <3.0.0dev,!=2.0.*,!=2.1.*,!=2.2.*,!=2.3.0",
+    "protobuf<4.0.0dev",
 ]
 extras = {"pandas": "pandas >= 0.17.1"}