Accept "sizePassthrough" prop

[bradennapier]

Ok - first pull request here so sorry if I did not follow any special rules to it :-).

Anyway, this just allows defining sizePassthrough with a boolean or a string. boolean will pass { size: { height, width } whereas string will pass { [this.props.sizePassthrough]: { height, width } }

You may have a better way you would want to handle this (if accepted) with the merge components. I simply name the sizePassthrough the string that it should add to the props and if the value is defined it sends it through.

[bradennapier]

Added updates to eslint configuration because it was failing for me with the given version. Fixed the eslint errors that it gave me throughout. All looks good now.

[codecov[bot]]

Codecov Report

Merging #81 into master will decrease coverage by 2.79%. The diff coverage is 66.66%.

@@            Coverage Diff            @@
##           master      #81     +/-   ##
=========================================
- Coverage   98.38%   95.58%   -2.8%     
=========================================
  Files           5        5             
  Lines          62       68      +6     
  Branches       16       18      +2     
=========================================
+ Hits           61       65      +4     
- Misses          0        2      +2     
  Partials        1        1

Impacted Files	Coverage Δ
src/componentQueries.js	95.83% <66.66%> (-4.17%)	:arrow_down:

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