Hi
Gitlab is perfectly fine to use for Julia packages, and so is any other git host. Github is used as the most common example because it is the most popular one and widely used within the Julia community (for better or worse), but it’s not necessary to use it.
PkgTemplates.jl has a Github Actions plugin, but right next to it you can see that it also has a GitLab CI (for handling continuous integration tasks when using Gitlab).
In the main Template call, you can see for the user keyword, it says “GitHub (or other code hosting service) username”.
And for host it says:
host::AbstractString="github.com": URL to the code hosting service where packages will reside.
i.e. "github.com" is the default if no host is specified, but you can instead specify your Gitlab instance’s URL here to use that instead.