[VOTE] PIP-300: Add custom dynamic configuration for plugins

[Zixuan Liu]

Hi Pulsar Community,

Voting for PIP-300: https://github.com/apache/pulsar/pull/21127
Discussion thread:
https://lists.apache.org/thread/ysnsnollgy1b6w1dsvmx1t1y2rz1tyd6

Thanks,
Zixuan