Add buildkite CI

[vchuravy]

• [DroneCI] Develop MPIPreferences
• remove old gitlab config
• also run CI against release- branches

[vchuravy]

@giordano Can drone also run Julia 1.7?

[giordano]

Drone uses the official julia docker images, which in turn rely on the official Julia binaries. We have had official binaries for aarch64 for pretty much all releases, so yes, you can use 1.7 too. I find it slightly easier to edit the (now gone) jsonnet file: you can't do a matrix in the yaml file, so you have to copy over everything for a different version of Julia

[vchuravy]

Hm despite doing a sync before passing the data we still see:

Test Failed at /var/lib/buildkite-agent/builds/gpuci-6/julialang/mpi-dot-jl/test/test_bcast.jl:25
  Expression: B == A
   Evaluated: Float32[0.29905963 0.23247325 … 0.81700486 0.6008139; 0.4981863 0.10537517 … 0.70482075 0.8041256; … ; 0.4952435 0.07156503 … 0.8349975 0.91180354; 0.38014913 0.05967331 … 0.52544254 0.11160207] == Float32[0.08002287 0.46079296 … 0.0022229552 0.53184825; 0.86832696 0.65267456 … 0.17802185 0.35201555; … ; 0.672473 0.40036875 … 0.8157358 0.19764471; 0.36474752 0.2532596 … 0.817343 0.5458178]
ERROR: LoadError: There was an error during testing
in expression starting at /var/lib/buildkite-agent/builds/gpuci-6/julialang/mpi-dot-jl/test/test_bcast.jl:21
--------------------------------------------------------------------------
Primary job  terminated normally, but 1 process returned
a non-zero exit code. Per user-direction, the job has been aborted.
--------------------------------------------------------------------------