Add ~ and ^ semver semantic to nimble "requires"

[marcomq]

Added ~ and ^ semver semantic to nimble "requires"
Check https://devhints.io/semver for semver examples
#907

[dom96]

Awesome, thank you!

Approving, but I'd like to see some docs for this, can you write some explaining what these new operators mean exactly in the readme? :)

[marcomq]

Thx for the review :) I will update the readme.
After checking the semver documentation again, I have to check if everything is still correct for 2 or 4 digit version numbers. Maybe I also need to add some test cases.

[marcomq]

Sry - after creating some documentation, I made some fixes and refactored a lot of code. However, I think the solution is better than my previous one. Let me know if I should make some additional changes.

[dom96]

Looks good, some suggestions for follow up:

• Create tests that verify the version range created for these new intersections, I think that is a much clearer way to test these :)

Might be possible to simplify getNextIncompatibleVersion, but let's get it merged, we can iterate later. As long as we have tests it's all good :)