Update scalastyle-sbt-plugin to 1.0.0

[fthomas]

This version is compatible with sbt 1.0.0 and allows to get rid of
a workaround for scalastyle/scalastyle-sbt-plugin#47.

It also complained about new issues which I've ignored for now. The same
issues already have been silenced in other places of the library.

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@2305ca6). Click here to learn what that means.
The diff coverage is 100%.

@@            Coverage Diff            @@
##             master    #1839   +/-   ##
=========================================
  Coverage          ?   94.96%           
=========================================
  Files             ?      241           
  Lines             ?     4193           
  Branches          ?      109           
=========================================
  Hits              ?     3982           
  Misses            ?      211           
  Partials          ?        0

Impacted Files	Coverage Δ
...ws/src/main/scala/cats/kernel/laws/OrderLaws.scala	100% <ø> (ø)
.../src/main/scala/cats/kernel/instances/bitSet.scala	100% <ø> (ø)
kernel/src/main/scala/cats/kernel/Comparison.scala	100% <100%> (ø)

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[non]

LGTM 👍