feat: add a protobuf extra

Author: BewareMyPower

.github/workflows/ci-pr-validation.yaml

@@ -78,7 +78,7 @@ jobs:
             python3 -m pip install -U pip setuptools wheel requests
             python3 setup.py bdist_wheel
             WHEEL=$(find dist -name '*.whl')
-            pip3 install ${WHEEL}[avro]
+            pip3 install ${WHEEL}[avro,protobuf]
 
       - name: Run Oauth2 tests
         run: |

setup.py

@@ -76,14 +76,21 @@ def build_extension(self, ext):
 
 extras_require = {}
 
+# protobuf schema dependencies
+extras_require["protobuf"] = sorted(
+    {
+      "protobuf>=3.6.1",
+    }
+)
+
 # functions dependencies
 extras_require["functions"] = sorted(
     {
-      "protobuf>=3.6.1",
       "grpcio>=1.59.3",
       "apache-bookkeeper-client>=4.16.1",
       "prometheus_client",
-      "ratelimit"
+      "ratelimit",
+      *extras_require["protobuf"],
     }
 )