The schema definition for the `<target>` node nested in an `<action>` node in a request allows for [an optional `repository` attribute](https://github.com/openSUSE/open-build-service/blob/d1200bdea2e989a6cadcb1182b849a3e2259b025/docs/api/api/request.rng#L110-L114), but [the corresponding model in osctiny](https://github.com/SUSE/osc-tiny/blob/d451ad7369c8eb97134cc7c7fb4e3e88192406cf/osctiny/models/request.py#L56-L67) doesn't.