Fix json parse example

[zsluedem]

This pr is trying to fix #272.

Currently the example in the readme can not actually work very well

[johnynek]

Thanks so much!

[codecov-commenter]

Codecov Report

Merging #274 (d366caf) into main (6fad586) will increase coverage by 0.10%.
The diff coverage is n/a.

❗ Current head d366caf differs from pull request most recent head fefde2d. Consider uploading reports for the commit fefde2d to get more accurate results

@@            Coverage Diff             @@
##             main     #274      +/-   ##
==========================================
+ Coverage   96.12%   96.22%   +0.10%     
==========================================
  Files           8        8              
  Lines         980      980              
  Branches       93       93              
==========================================
+ Hits          942      943       +1     
+ Misses         38       37       -1     

Impacted Files	Coverage Δ
core/shared/src/main/scala/cats/parse/Parser.scala	96.10% <0.00%> (+0.12%)	⬆️

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[zsluedem]

@johnynek Got some import error . Force push already.