Support for Gitlab CI

[sakoarts]

Great project, would love to use it! Sadly I'm currently running my project within Gitlab and also using Gitlab CI functionality to deploy the server side of my ESP32 project. I'm considering forking this project to have it support Gitlab as well as Github. Creating the Gitlab CI alternative of the Gitlab Action build step won't be much of a problem. I'm now wondering whether the part where it creates a release (which Gitlab has as well) and moreover, the part where it polls the Github API for a new version is very Github-specific or if it would be pretty doable to repurpose that for a different API. Would love to hear your thoughts on this.