Fix JL_SKIP_LIB_CHECK installation

[odow]

Closes #468

@nickrobinson251 can you test this branch please?

[codecov]

Codecov Report

Merging #469 (1357f11) into master (952620f) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #469   +/-   ##
=======================================
  Coverage   59.30%   59.30%           
=======================================
  Files           8        8           
  Lines        3720     3720           
=======================================
  Hits         2206     2206           
  Misses       1514     1514           

Impacted Files	Coverage Δ
src/Gurobi.jl	0.00% <ø> (ø)

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[nickrobinson251]

Thanks!

Yes, tested this branch out on the same CI setup and it works -- thanks again for the quick fix!