add semver as version scheme

[tschmidtb51]

I suggest to add a version scheme semver that as defined by https://semver.org/

Flagging @pombredanne for attention

[immqu]

As far as I can see, the semver spec does not say anything about how to specify a version range. Should we still allow for a certain way to specify a semver-native range in univers, like ">1.0.2|<2.0.0", or simply leave it out (such that there would be no from_native method in univers for semver)?

[tschmidtb51]

@pombredanne Feel free to correct me here:

As it is not specified in SemVer, I guess we should not have that. I guess that would also be in line with what is done for Debian and RPM.

[immqu]

Actually, univers already implements a semver versioning scheme. See also the tests.

It seems also that no semver versioning range is implemented (as we discussed above), so as far as I can tell, this issue is already resolved in univers.

[tschmidtb51]

Actually, univers already implements a semver versioning scheme. See also the tests.

Perfect. So it just needs to be added to vers.