(apro) kubernaut-ui.mk: Avoid warnings from `make` inside of `make shell`
(apro) kubernaut-ui.mk: Avoid warnings from `make` inside of `make shell`

    $ make shell
    (dev) $ make help
    make: warning: jobserver unavailable: using -j1.  Add '+' to parent make rule.
    Usage: make [TARGETS...]
    …

datawire/ambassador,datawire/ambassador,datawire/ambassador,datawire/ambassador,datawire/ambassador