Upgrade Play & Play JSON to 3.0

[gaeljw]

Supersedes #380

• Play JSON 3.0 is identical to Play JSON 2.10.1 playframework/play-json@2.10.1...3.0.0, it's only a groupId renaming of the artifact (com.typesafe.play -> org.playframework)
• Play 3.0 brings new features/bugfixes, drop support for Scala 2.12 and uses Pekko instead of Akka (though it seems to me that enumeratum code is unrelated to Pekko/Akka)

As discussed in #380, Play 2.x support is discontinued in favour of Play 3.x unless there is a strong demand for it.

Closes #382

[gaeljw]

@lloydmeta It's not clear to me why the exclude("org.scala-lang.modules", "*") is present, I kept it in doubt but maybe it's not needed anymore?

[gaeljw]

I don't understand why 2.12 build fails but for sure it's related to my attempt to not build enumeratum-play for 2.12 anymore. Will investigate a bit more tomorrow. Unless you've got any idea.

[codecov-commenter]

Codecov Report

Merging #381 (6b0828e) into master (dba1630) will increase coverage by 0.19%.
The diff coverage is n/a.

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@@            Coverage Diff             @@
##           master     #381      +/-   ##
==========================================
+ Coverage   85.52%   85.71%   +0.19%     
==========================================
  Files          65       63       -2     
  Lines         518      511       -7     
  Branches       31       34       +3     
==========================================
- Hits          443      438       -5     
+ Misses         75       73       -2     

see 5 files with indirect coverage changes

[gaeljw]

I don't understand why 2.12 build fails but for sure it's related to my attempt to not build enumeratum-play for 2.12 anymore. Will investigate a bit more tomorrow. Unless you've got any idea.

Wow.. this was tricky but I think I got it: from what I understand, the commands used in CI were not actually doing what you'd think. The sbt ++<version> cmd1 cmd2 was running only cmd1 with the desired Scala version, cmd2 was running on all Scala versions. Sounds a bit weird, not sure I understood everything to be honest.

This is the reason I had to make changes to CI:

• actually run all commands with the desired Scala version
• use Scala 2.13 for scalafmtCheck and coverage reports (otherwise we lose coverage for enumeratum-play which is not available in 2.12)
• fix style so that scalafmt (on compile) runs without error with Scala 3 (it was failing on a macro, not sure why, just disabled it)

I've done several commits but happy to move these unrelated changes to another PR first if you prefer to.

[lloydmeta]

LGTM. Just holding on merging until I get time to also release.

[lloydmeta]

Thanks for this. Just pushed 1.8.0 of the Play integration libs to Maven central based on this.

[gaeljw]

Great news :)