I'm working on update npm libraries (third-party packages) but I dont know to name branch: feature, hotfix, another?.
What do you recommends me?
That would be a feature branch, used to isolate a development effort.
In your case: feature/upgradetp, to test in your own branch the upgrade of third-party packages.
If that works, then you can merge in develop for integration testing, and finally master for release.
Atlassian has a nice presentation of feature branch as part of a workflow:
The core idea behind the Feature Branch Workflow is that all feature development should take place in a dedicated branch instead of the main branch.
This encapsulation makes it easy for multiple developers to work on a particular feature without disturbing the main codebase.
It also means the main branch will never contain broken code, which is a huge advantage for continuous integration environments.
Same idea with Mergify's decription of feature branch.
Another name is "topic branch", used with gitworkflow, that I present here.