Alleviating MSRV issues

[akern40]

Our CI/CD keeps breaking due to problems with MSRV, especially for our BLAS setup. I suggest the following steps to alleviate this:

1. Check in Cargo.lock, increasing the determinism of our CI/CD jobs
2. Add a GitHub workflow that periodically checks against new dependencies, once for the MSRV and once without MSRV, but in both cases using the MSRV-aware resolver