Pin protobuf to 3.20.0 in python layer (#268)

Author: vasireddy99

.github/workflows/pr-python.yml

@@ -3,13 +3,12 @@ name: "Pull Request (Python)"
 on:
   pull_request:
     paths:
-    - 'python/**'
+      - 'python/**'
     branches:
       - main
 
 env:
   AWS_REGION: us-east-1
-  CORE_REPO_SHA: 281c97bf8f9e31392859e006e13c9c8eac8967c3
 
 jobs:
   PR-Python:

python/src/otel/otel_sdk/requirements.txt

@@ -1,3 +1,4 @@
 opentelemetry-exporter-otlp-proto-http==1.11.1
 opentelemetry-distro==0.30b1
-opentelemetry-instrumentation-aws-lambda==0.30b1
+opentelemetry-instrumentation-aws-lambda==0.30b1
+protobuf==3.20.0