Use semver-compatible nightly versions

[onbjerg]

Once we cut a stable release we should ditch the nightly-<sha> versions and instead use something semver compatible, e.g. x.y.z-nightly.n+<sha>, where:

• x.y.z is the next version to be released, or just the latest version with a minor patch (e.g. if latest is x.y.z, then we would use x.y.(z+1))
• -nightly.n is the prerelease label (as per semver spec), which is used to order releases (which is why n would be the nightly number)
• +<sha> is metadata that semver does not consider for version ordering

For example, this would be the order of a number of releases and their pre-releases (first one is latest)

1.1.0
1.1.0-nightly.2+abcdef
1.1.0-nightly.1+abcdef
1.1.0-nightly.0+abcdef
1.0.0

This is a breaking change so it should only be considered in the new foundryup. Additionally this requires changes to the release workflow

[sambacha]

https://github.com/sambacha/foundry-tags