When a pull request is opened, will deploy that branch to `<reponame>-<branchname>.branch.dsv.su.se` with branch name having `/` replaced with `-` and all characters that do not match `[a-z0-9-]` are removed.
Co-authored-by: Andreas Svanberg <andreass@dsv.su.se>
Co-committed-by: Andreas Svanberg <andreass@dsv.su.se>
