Investigate use of PkgLock.jl to avoid race conditions on module precompilation with MPI

[sloede]

You could also use PkgLock.jl to precompile all packages without race conditions and use them afterwards in parallel.

Xref: https://discourse.julialang.org/t/precompilation-error-using-hpc/17094

Originally posted by @ranocha in #167 (comment)

We should check if and how it makes sense to include it in our testing environment, and maybe document it for use on clusters etc.

[ranocha]

Maybe we can also just sit this out: JuliaLang/julia#36416

[ranocha]

I've tested it on the current Julia nightly: We won't need the flag --compiled-modules=no on Julia v1.6 anymore 🎉

[sloede]

Excellent news! Do you know if there's a tentative release date for 1.6?

[ranocha]

The soft feature freeze is today: https://discourse.julialang.org/t/1-6-soft-feature-freeze-nov-8th/49379. Then, we will have the usual release process (finishing works, alpha, beta, iterate RCs until convergence) I guess. Usually, there isn't a tentative schedule for this last part of the process.