upgrade protobuf

requirements.txt

-grpcio>=1.28.1
-grpcio_tools>=1.28.1
-protobuf==3.9.0
\ No newline at end of file
+grpcio
+grpcio_tools
+protobuf
\ No newline at end of file

setup.cfg

@@ -20,5 +20,5 @@ python_requires = >=3.7
 zip_safe = False
 setup_requires = setuptools_scm
 install_requires =
-    grpcio==1.28.1
-    protobuf==3.9.0
\ No newline at end of file
+    grpcio
+    protobuf
\ No newline at end of file