Decode not nessesary here

[alex-eri]

fixes #294

[codecov]

Codecov Report

Merging #295 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #295   +/-   ##
=======================================
  Coverage   97.08%   97.08%           
=======================================
  Files           4        4           
  Lines         206      206           
  Branches       25       25           
=======================================
  Hits          200      200           
  Misses          4        4           
  Partials        2        2

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[asvetlov]

The PR changes semantix.
Was "encoder/decoder are convertes between object and str".
Now "decoder is a converter from str to object if it is exactly json.loads, otherwise it converts from bytes to object. Encoder semantics is not changed".

Sorry, cannot accept such change. It is at least not backward compatible.