devel/gitflow: update to 1.11.0

• Update LICENSE
• Update GH_* variables to the new repository
• Update comment and WWW in pkg-descr

Changelog: https://github.com/petervanderdoes/gitflow-avh/releases/tag/1.11.0

PR: 223399
Submitted by: Aldis Berjoza <aldis@berjoza.lv>
Approved by: Nicolas Embriz <nbari@tequila.io> (maintainer)