For workflows like `cargo info`, this call will live on regardless of
what we do with the resolver.

We do this by resolving for a package version that is compatible
with the most number of MSRVs within a workspace.

If a version requirement is just right, every package will get the
highest MSRV-compatible dependency.

If its too high, packages will get MSRV-incompatible dependency
versions.
This will happen regardless of what we do due to the nature of
`"fallback"`.

If its too low, packages with higher MSRVs will get older-than-necessary
dependency versions.
This is similar to the "some with and without MSRV" workspaces.
When locking dependencies, we do report to users when newer MSRV/SemVer
compatible dependencies are available to help guide them to upgrading if
desired.

Fixes rust-lang#14414