Update default branch to 3.x on Gitlab

Problem/Motivation

Thanks for a great module, it works perfectly.

Since the current stable release is 3.0.0, perhaps the 3.x branch can be the default on Gitlab as well (currently it's 2):

https://git.drupalcode.org/project/formdazzle

Also, the doc link on the project page could get simplified, form "Documentation for Formdazzle! 2.x" to just "Documentation for Formdazzle!" for less future maintenance.

Thanks!

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes