Update Kokkos package to fix GitLab CI

[rbberger]

PR Summary

One of the GitLab builds requires Kokkos to be compiled with +cuda_constexpr. However, the current CI upstream has an outdated Kokkos package. This PR adds the spackage to fix this until the CI upstream is updated.

PR Checklist

• [ ] Code is formatted.
• [ ] Adds a test for any bugs fixed. Adds tests for new features.

[Yurlungur]

Thanks for finding this! As we discussed, I was able to resolve the issue by removing the reliance on cuda-relaxed-constexpr in the relevant test. I also changed the number of points to make the test faster. Things seem to work now.

[Yurlungur]

Resolved in #47