fix deprecation warning (loader-utils)

[helloyou2012]

see: webpack/loader-utils#56

[codecov]

Codecov Report

Merging #428 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master     #428   +/-   ##
=======================================
  Coverage   98.35%   98.35%           
=======================================
  Files           9        9           
  Lines         304      304           
  Branches       67       69    +2     
=======================================
  Hits          299      299           
  Misses          5        5

Impacted Files	Coverage Δ
lib/loader.js	100% <100%> (ø)	✅
lib/localsLoader.js	100% <100%> (ø)	✅

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[michael-ciniawsky]

@helloyou2012 Thx

@bebraw @d3viant0ne