fix(pkg): remove extra yarn.lock from npm package

[pi0]

The yarn.lock file which is included in npm packages has 220K overhead which is ignored by yarn according to the docs

[codecov]

Codecov Report

Merging #287 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master    #287   +/-   ##
======================================
  Coverage    40.3%   40.3%           
======================================
  Files          18      18           
  Lines         263     263           
======================================
  Hits          106     106           
  Misses        157     157

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