Granting permissions to one Mercurial branch

[Luis Falcon]

Dear all

We need to be able to push the translations changes from
Weblate to our "default" branch.

Is it possible to do it? 

We could create a developer user, but that would give access to many
resources. We only need weblate to be able to commit / push to the
default branch.  I've got the RSA key from the Weblate server.

Thanks!
Luis