Fix CI make compress

[sapk]

Fix a bug intorduced by me in #3991 since xgo image doesn't seems to have gopath/bin folder in path.
So I add $GOPATH/bin to PATH for make releases

For reference : https://github.com/karalabe/xgo/blob/master/docker/base/Dockerfile

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@45f3d4a). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master    #4020   +/-   ##
=========================================
  Coverage          ?   20.05%           
=========================================
  Files             ?      153           
  Lines             ?    30344           
  Branches          ?        0           
=========================================
  Hits              ?     6086           
  Misses            ?    23345           
  Partials          ?      913

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