Bug 31684: Plugin versions starting with a "v" cause unnecessary warnings

Bug 31684: Plugin versions starting with a "v" cause unnecessary warnings

Our code assumes that plugin version will be purely numeric ( e.g. 1.2.3 ) but many plugin authors ( including myself ) use the format "v1.2.3".
This causes warnings as we use a numeric comparison on the version numbers.
It could make sense to check for and strip any v's from the beginning of the version.

Test Plan:
1) Apply the first patch to set the test plugin's version to v1.01
2) prove t/db_dependent/Koha/Plugins/Plugins.t
3) Note the warnings and test failures
4) Apply this patch
5) prove t/db_dependent/Koha/Plugins/Plugins.t
6) All tests pass!

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>