update to sbt 1.3.x, uses coursier by default

[larsrh]

Includes & supersedes #2954, #3075, #3077.

Open problems:

• for some reason, the BC tests won't work when Coursier is used (we can choose to ignore this)
• see Update sbt-mima-plugin to 0.4.0 #2934 for some details on the generic signature problem, but since then a bunch of additional errors surfaced (see below, blocker)

[error]  * static method catsParallelForEitherTNestedValidated(cats.Monad,cats.kernel.Semigroup)cats.Parallel in class cats.implicits does not have a correspondent in current version
[error]    filter with: ProblemFilters.exclude[DirectMissingMethodProblem]("cats.implicits.catsParallelForEitherTNestedValidated")
[error]  * static method catsParallelForEitherTNestedParallelValidated(cats.kernel.Semigroup,cats.Parallel)cats.Parallel in class cats.implicits does not have a correspondent in current version
[error]    filter with: ProblemFilters.exclude[DirectMissingMethodProblem]("cats.implicits.catsParallelForEitherTNestedParallelValidated")
[error]  * static method catsParallelForOptionTNestedOption(cats.Parallel)cats.Parallel in class cats.implicits does not have a correspondent in current version
[error]    filter with: ProblemFilters.exclude[DirectMissingMethodProblem]("cats.implicits.catsParallelForOptionTNestedOption")
[error]  * static method catsStdEqForSortedMap(cats.kernel.Order,cats.kernel.Eq)cats.kernel.Eq in class cats.implicits does not have a correspondent in current version
[error]    filter with: ProblemFilters.exclude[DirectMissingMethodProblem]("cats.implicits.catsStdEqForSortedMap")
[error]  * static method catsStdMonoidForSortedMap(cats.kernel.Order,cats.kernel.Semigroup)cats.kernel.Monoid in class cats.implicits does not have a correspondent in current version
[error]    filter with: ProblemFilters.exclude[DirectMissingMethodProblem]("cats.implicits.catsStdMonoidForSortedMap")
[error]  * static method catsStdCommutativeMonoidForSortedMap(cats.kernel.Order,cats.kernel.CommutativeSemigroup)cats.kernel.CommutativeMonoid in class cats.implicits does not have a correspondent in current version
[error]    filter with: ProblemFilters.exclude[DirectMissingMethodProblem]("cats.implicits.catsStdCommutativeMonoidForSortedMap")
[error]  * static method catsStdHashForSortedMap(cats.kernel.Hash,cats.kernel.Order,cats.kernel.Hash)cats.kernel.Hash in class cats.implicits does not have a correspondent in current version
[error]    filter with: ProblemFilters.exclude[DirectMissingMethodProblem]("cats.implicits.catsStdHashForSortedMap")
[error]  * static method catsKernelStdSemilatticeForSortedSet(cats.kernel.Order)cats.kernel.BoundedSemilattice in class cats.implicits does not have a correspondent in current version
[error]    filter with: ProblemFilters.exclude[DirectMissingMethodProblem]("cats.implicits.catsKernelStdSemilatticeForSortedSet")

[kailuowang]

I am on my phone. I wonder what happened to those methods. Will take a look them Monday

[kailuowang]

Okay, these are indeed BC breakages that were missed by previous Mima versions.
Discussion can be found here
TLDR; making a public method package private in an object (in our case cats.implicts) breaks BC for Java usage. So these were not caught in the wide because only java usage exposes them.

Looks like we need to remove the package private on these methods. Shall we do them in this PR? Then we probably want to cherry pick to 2.0.x branch and release a patch.

[larsrh]

Are those supposed to be deprecated? I can do that in this PR.

[kailuowang]

Yes. Those methods were moved to somewhere else. They are kept at the original place deprecated to maintain BC. Making them package private was an extra measure (now proven invalid) for the deprecation.

[larsrh]

If the build is green, I'll rebase & reorder for easier cherry-picking.

[codecov-io]

Codecov Report

Merging #3079 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3079   +/-   ##
=======================================
  Coverage   93.46%   93.46%           
=======================================
  Files         368      368           
  Lines        6979     6979           
  Branches      184      184           
=======================================
  Hits         6523     6523           
  Misses        456      456

Impacted Files	Coverage Δ
core/src/main/scala/cats/instances/sortedSet.scala	88.23% <ø> (ø)	⬆️
core/src/main/scala/cats/data/Op.scala	77.77% <ø> (ø)	⬆️
core/src/main/scala/cats/instances/parallel.scala	0% <ø> (ø)	⬆️
core/src/main/scala/cats/instances/sortedMap.scala	84.74% <ø> (ø)	⬆️

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[larsrh]

Ready for review.

[fthomas]

Could you also bump the sbt version in scalafix/project/build.properties?

[kailuowang]

Thanks very much @larsrh for taking this on.