Add protobuf libraries as default dependency since long term goal is to build a2a types from proto files

Author: aneeshgarg

pyproject.toml

@@ -15,7 +15,9 @@ dependencies = [
   "opentelemetry-sdk>=1.33.0",
   "pydantic>=2.11.3",
   "sse-starlette",
-  "starlette"
+  "starlette",
+  "protobuf==5.29.5",
+  "google-api-core>=1.26.0",
 ]
 
 classifiers = [
@@ -37,7 +39,7 @@ mysql = ["sqlalchemy[asyncio,aiomysql]>=2.0.0"]
 sqlite = ["sqlalchemy[asyncio,aiosqlite]>=2.0.0"]
 sql = ["sqlalchemy[asyncio,postgresql-asyncpg,aiomysql,aiosqlite]>=2.0.0"]
 encryption = ["cryptography>=43.0.0"]
-grpc = ["grpcio>=1.60", "grpcio-tools>=1.60", "grpcio_reflection>=1.7.0", "protobuf==5.29.5", "google-api-core>=1.26.0"]
+grpc = ["grpcio>=1.60", "grpcio-tools>=1.60", "grpcio_reflection>=1.7.0"]
 
 [project.urls]
 homepage = "https://a2a-protocol.org/"