spack: add 1.6.0 release and ports-of-call 1.3.0

[rbberger]

PR Summary

PR Checklist

• [ ] Code is formatted. (You can use the format_spiner make target.)
• [ ] Adds a test for any bugs fixed. Adds tests for new features.
• [ ] If preparing for a new release, update the version in cmake.

[rbberger]

@Yurlungur Same thing here. Basically the problem originates from spiner and also affects singularity-eos builds on the re-git CI.

[rbberger]

@Yurlungur This can be merged.