Backport MiMa config and dependency updates for 2.11

[travisbrown]

Includes #3129 plus all the dependency updates. I've not cherry-picked the Scala Steward commits individually because who has time for that.

I've also added #3125 and #3135.

/cc @jackcviers

[codecov-io]

Codecov Report

Merging #3142 into scala_2.11 will increase coverage by 0.1%.
The diff coverage is 85.71%.

@@             Coverage Diff              @@
##           scala_2.11   #3142     +/-   ##
============================================
+ Coverage        93.4%   93.5%   +0.1%     
============================================
  Files             382     382             
  Lines            7155    7147      -8     
  Branches          195     194      -1     
============================================
  Hits             6683    6683             
+ Misses            472     464      -8

Impacted Files	Coverage Δ
core/src/main/scala/cats/instances/sortedSet.scala	88.23% <ø> (ø)	⬆️
core/src/main/scala/cats/instances/sortedMap.scala	84.74% <ø> (ø)	⬆️
core/src/main/scala/cats/instances/parallel.scala	0% <0%> (ø)	⬆️
core/src/main/scala/cats/data/NonEmptyList.scala	99.33% <100%> (ø)	⬆️
core/src/main/scala/cats/data/NonEmptyVector.scala	99.13% <100%> (ø)	⬆️
core/src/main/scala/cats/instances/option.scala	100% <100%> (ø)	⬆️
.../src/main/scala/cats/laws/discipline/MiniInt.scala	97.29% <100%> (ø)	⬆️

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