MassInstallAction: Install the CompatHelper workflow on this repository

[timholy]

This pull request sets up the CompatHelper workflow on this repository.

[codecov]

Codecov Report

Merging #7 (8e2c854) into master (46fe032) will increase coverage by 1.73%.
The diff coverage is n/a.

❗ Current head 8e2c854 differs from pull request most recent head d722da4. Consider uploading reports for the commit d722da4 to get more accurate results

@@            Coverage Diff             @@
##           master       #7      +/-   ##
==========================================
+ Coverage   78.78%   80.51%   +1.73%     
==========================================
  Files           2        2              
  Lines          66       77      +11     
==========================================
+ Hits           52       62      +10     
- Misses         14       15       +1     

Impacted Files	Coverage Δ
src/symrange.jl	67.85% <0.00%> (+1.19%)	⬆️
src/CenterIndexedArrays.jl	87.75% <0.00%> (+2.04%)	⬆️

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