Update frontend dependencies

[dominik-zeglen]

Closes #1114

[maarcingebala]

It looks like part of this PR is also covered by PR #1113. Could you make sure that we don't double commits in two different pull requests?

[maarcingebala]

Also please follow this guidelines for writing commit messages.

[patrys]

It seems that CI fails: https://travis-ci.org/mirumee/saleor/builds/274641837

[patrys]

@dominik-zeglen Once you fix CI please rewrite the commits to follow what @elwoodxblues suggested.

[codecov-io]

Codecov Report

Merging #1115 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master    #1115   +/-   ##
=======================================
  Coverage   67.68%   67.68%           
=======================================
  Files         114      114           
  Lines        6140     6140           
  Branches      747      747           
=======================================
  Hits         4156     4156           
  Misses       1812     1812           
  Partials      172      172

Impacted Files	Coverage Δ
saleor/graphql/api.py	81.92% <100%> (ø)	⬆️

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[maarcingebala]

I think we could also bump the version of Yarn in this PR.

[ghost]

With new "materialize-css" version = 0.100.2 not working checkbox in dashboard

[benekex2]

You should use module.rules instead of old module.loaders syntax.
https://webpack.js.org/guides/migrating/#module-loaders-is-now-module-rules