expand CI matrix to cover broader platform configurations

[vtjnash]

No description provided.

[codecov]

Codecov Report

Merging #30 (59be707) into master (5caf444) will increase coverage by 0.37%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #30      +/-   ##
==========================================
+ Coverage   92.11%   92.49%   +0.37%     
==========================================
  Files           1        1              
  Lines         279      293      +14     
==========================================
+ Hits          257      271      +14     
  Misses         22       22              

Impacted Files	Coverage Δ
src/Glob.jl	92.49% <0.00%> (+0.37%)	⬆️

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[coveralls]

Coverage increased (+0.0%) to 91.756% when pulling 59be707 on jn/expand-matrix into 5caf444 on master.