Add a way to "rename" a package's version

[jrray]

The intended use case is for taking a pre-release build and making it "official" (de-pre it).

Say you've built my-pkg/1.2.3-pre.1 and after testing you're happy with it and want to make it my-pkg/1.2.3. You could update the version and rebuild the package, but this introduces uncertainty that you'll get a build again that matches what you were testing before. For example, since the build environment is re-solved you could end up with different versions of your build dependencies and end up with a different binary.

A version rename tool could be used improperly in all sorts of ways, but it is the best way to accomplish this specific use case. There was a request to be able to rename from one pre-release version to another pre-release version because it was causing problems. There will always be odd ball use cases that look like they could be dangerous in general but would be safe in some circumstances.

[rydrman]

From the meeting today:

• I would also like to be able to transfer packages, maybe it's not related but a possible copy functionality could do this
• is there not a folder or metadata in the package with the version that would affect the filesystem hash?
• there is so that would need to be updated
• how can we be sure that the build script wouldn't have behaved differently - maybe that's at the risk of the user?
• or we limit it to removing pre/post tags?