There are existing packages out there whose version do not conform to SemVer,
yet, one would like to have them available in a generic package repository. To
this end, remove the SemVer restriction on package versions when using the
Generic package registry, and replace it with a check that simply makes sure the
version isn't empty.

Signed-off-by: Gergely Nagy <me@gergo.csillger.hu>

Co-authored-by: KN4CK3R <admin@oldschoolhack.me>

Co-authored-by: KN4CK3R <admin@oldschoolhack.me>

Instead of just checking against the space-trimmed version string, return the
same trimmed version too, so it gets used in that form down the line.

Also add `strings` to the list of imports, because of our use of TrimSpace.

Signed-off-by: Gergely Nagy <me@gergo.csillger.hu>

Co-authored-by: KN4CK3R <admin@oldschoolhack.me>

Signed-off-by: Gergely Nagy <me@gergo.csillger.hu>