Disable docbot for the pulsar-site repository

[visortelle]

Hi 👋
Docbot automatically label pull requests based on the checked task list.

I wonder, does the "docbot" bring any value to the https://github.com/apache/pulsar-site repo?

The content of this repo is mostly docs itself.

PRs don’t implement any features that require docs. If they are, it's rather an exception.

Maybe I'm missing something.

cc @lhotari @tisonkun

[lhotari]

+1000

[visortelle]

OK. Then I'll prepare a PR for this a bit later. 🙂