setItem mutation param

[benitogf]

#27

[codecov]

Codecov Report

Merging #28 into master will increase coverage by 6.74%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #28      +/-   ##
==========================================
+ Coverage   84.07%   90.81%   +6.74%     
==========================================
  Files           4        4              
  Lines         113       98      -15     
  Branches       36       25      -11     
==========================================
- Hits           95       89       -6     
+ Misses          8        2       -6     
+ Partials       10        7       -3

Impacted Files	Coverage Δ
src/MockStorage.ts	100% <100%> (ø)	⬆️
src/index.ts	88.88% <100%> (+9.43%)	⬆️
build/rollup.config.js
rollup.config.js	100% <0%> (ø)
src/SimplePromiseQueue.ts	87.5% <0%> (+4.16%)	⬆️

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[championswimmer]

somehow there are a lot of conflicts, and I don't understand why. those are files untouched by you. probably new lines are not same on our operating systems