Adit Chawdhary

[improve][function] Introduced protections against deserialization attacks

3

### Motivation This change hardens Java deserialization operations against attack. Even a simple operation like an object deserialization is an opportunity to yield control of your system to an attacker....

[Bug][build] maven package -Dmaven.test.skip is broken

2

### Search before asking - [X] I searched in the [issues](https://github.com/apache/pulsar/issues) and found nothing similar. ### Read release policy - [X] I understand that unsupported versions don't get bug fixes....

add pip installation command in installation guide