Revert "Merge pull request #137 from aws/dependabot/pip/protobuf-3.20.2"

This reverts commit 74466b4, reversing
changes made to 7a837c7.

Author: dewan-c

requirements.txt

@@ -8,7 +8,7 @@ model-archiver==1.0.3
 multi-model-server==1.1.1
 numpy==1.19.2
 pandas==1.1.3
-protobuf==3.20.2
+protobuf==3.20.1
 psutil==5.7.2
 python-dateutil==2.8.1
 sagemaker-inference==1.2.0