[fix][ci][branch-2.10] Fix the release tools (#19711)

## Modification
1. Upgrade python to python3
2. Remove the cpp-related command

Author: liangyepianzhou

src/get-project-version.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 #
 # Licensed to the Apache Software Foundation (ASF) under one
 # or more contributor license agreements.  See the NOTICE file

src/stage-release.sh

@@ -38,12 +38,6 @@ cp $PULSAR_PATH/distribution/offloaders/target/apache-pulsar-offloaders-$VERSION
 
 cp -r $PULSAR_PATH/distribution/io/target/apache-pulsar-io-connectors-$VERSION-bin $DEST_PATH/connectors
 
-mkdir $DEST_PATH/RPMS
-cp -r $PULSAR_PATH/pulsar-client-cpp/pkg/rpm/RPMS/x86_64/* $DEST_PATH/RPMS
-
-mkdir $DEST_PATH/DEB
-cp -r $PULSAR_PATH/pulsar-client-cpp/pkg/deb/BUILD/DEB/* $DEST_PATH/DEB
-
 # Sign all files
 cd $DEST_PATH
 find . -type f | grep -v LICENSE | grep -v README | xargs $PULSAR_PATH/src/sign-release.sh