SPath release for SCR v3.0

[CamStan]

See SCR v3.0 project: https://github.com/LLNL/scr/projects/4

Process

• Resolve necessary issues
• Merge any existing PRs
• Create a commit(s) which updates the project version number in the code and updates references to any dependency versions.
• Merge the commit
• Tag a release on GitHub
• Add release note (can be done after the release is tagged)
• Update the spack package, both with the version hash and the dependency versions.