Fix python3 UnicodeDecodeError when use websocket

[leavest]

Fixes kubernetes-client/python/issues#717
Fixes #88
in python3

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[codecov-io]

Codecov Report

Merging #129 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #129   +/-   ##
=======================================
  Coverage   92.84%   92.84%           
=======================================
  Files          13       13           
  Lines        1328     1328           
=======================================
  Hits         1233     1233           
  Misses         95       95

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[leavest]

I signed it