feat: support prerelease version increments

[Andrapyre]

This PR adds support for incrementing prerelease versions by default, if it ends in a number. Currently, if a prerelease version is incremented, the prerelease qualifier is simply dropped. E.g. 1.0.0-RC1 will be incremented to 1.0.0. After this merge, 1.0.0-RC1 will be incremented to 1.0.0-RC2, but prerelease versions without a version number will behave as before: 1.0.0-alpha will be incremented to 1.0.0.

Additionally, the .asSnapshot method will include the prerelease version. E.g. 1.0.0-RC1 will return 1.0.0-RC1-SNAPSHOT.

This PR also adds type declarations for public members in the Version class, as well as some ScalaDocs.

[Andrapyre]

@xuwei-k , is this project still active? It looks like it's been two years since the last release. Not sure if you're open to taking on any official maintainers, but happy to help in that way or just with regular contributions. This plugin has been super helpful in my work. Thanks for keeping it going!

[xuwei-k]

Please revert some unnecessary changes.

[Andrapyre]

@xuwei-k , I've removed all changes to build.sbt except standardizing the scala version. I also realized that .withoutQualifier is no longer being used in the code base after my changes, so I've marked it as deprecated in favor of .withoutSnapshot.

[Andrapyre]

@xuwei-k , I've reverted the scala version change, as you've requested, but just curious for some context - isn't it best practice to declare scala versions in the build config so as to avoid different local environments building with a different scala version?

[Andrapyre]

@xuwei-k , now that the changes to build.sbt are reverted, would you be able to merge this PR?

[SethTisue]

isn't it best practice to declare scala versions in the build config so as to avoid different local environments building with a different scala version?

sbt plugins are a bit unusual in this respect. The Scala version used is determined by the sbt version being used, so it's not really necessary to also pin the Scala version by other means.