CompatHelper: bump compat for Setfield to 0.8, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the Setfield package from 0.5.1, 0.6, 0.7 to 0.5.1, 0.6, 0.7, 0.8.
This keeps the compat entries for earlier versions.

Note: I have not tested your package with this new compat entry.
It is your responsibility to make sure that your package tests pass before you merge this pull request.

[codecov]

Codecov Report

Merging #216 (82ab463) into master (a104913) will increase coverage by 0.05%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #216      +/-   ##
==========================================
+ Coverage   90.75%   90.80%   +0.05%     
==========================================
  Files          22       22              
  Lines         519      533      +14     
==========================================
+ Hits          471      484      +13     
- Misses         48       49       +1     

Flag	Coverage Δ
unittests	90.80% <ø> (+0.05%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/base.jl	83.46% <0.00%> (-0.41%)	⬇️
src/collectors.jl	100.00% <0.00%> (ø)
src/NoBang/singletonof.jl	100.00% <0.00%> (ø)
src/NoBang/base.jl	89.53% <0.00%> (+0.24%)	⬆️
src/dataframes_impl.jl	93.47% <0.00%> (+0.79%)	⬆️

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