protobuf ceiling bump (#26271)

resolves #25398

## How I Tested These Changes

existing coverage

python_modules/dagster/setup.py

@@ -87,8 +87,8 @@ def get_version() -> str:
         f"grpcio>={GRPC_VERSION_FLOOR}",
         f"grpcio-health-checking>={GRPC_VERSION_FLOOR}",
         "packaging>=20.9",
-        "protobuf>=3.20.0,<5; python_version<'3.11'",  # min protobuf version to be compatible with both protobuf 3 and 4
-        "protobuf>=4,<5; python_version>='3.11'",
+        "protobuf>=3.20.0,<6; python_version<'3.11'",  # min protobuf version to be compatible with both protobuf 3 and greater
+        "protobuf>=4,<6; python_version>='3.11'",
         "python-dotenv",
         "pytz",
         "requests",

python_modules/libraries/dagster-mlflow/setup.py

@@ -32,6 +32,11 @@ def get_version() -> str:
     packages=find_packages(exclude=["dagster_mlflow_tests*"]),
     include_package_data=True,
     python_requires=">=3.9,<3.13",
-    install_requires=[f"dagster{pin}", "mlflow", "pandas"],
+    install_requires=[
+        f"dagster{pin}",
+        "mlflow",
+        "pandas",
+        "protobuf!=5.29.0",  # https://github.com/protocolbuffers/protobuf/issues/19430
+    ],
     zip_safe=False,
 )