Update dependency protobuf to v3.20.3

Author: renovate[bot]

requirements-min.txt

@@ -1,5 +1,5 @@
 # Minimum package versions that ONNX supports
-protobuf==3.20.2; python_version<"3.12"
+protobuf==3.20.3; python_version<"3.12"
 protobuf==4.25.1; python_version>="3.12"
 numpy==1.20.3; python_version<"3.10"
 numpy==1.23.2; python_version=="3.10"