publishing: bye Bintray, hello Sonatype

[SethTisue]

modeled after playframework/play-json#603

[SethTisue]

@octonato can you add the Play publishing secrets to the Travis-CI config...?

[SethTisue]

plugin/scripted fails with:

[info] Running 2 / 2 (100.00%) scripted tests with RunFromSourceMain
[info] Running twirl/compile
[error] [info] [launcher] getting org.scala-sbt sbt 1.5.5  (this may take some time)...
[error] [info] [launcher] getting Scala 2.12.14 (for sbt)...
[info] [info] Updated file /tmp/sbt_c4eaddbe/project/build.properties: set sbt.version to 1.5.5
[info] [info] welcome to sbt 1.5.5 (AdoptOpenJDK Java 11.0.11)
[error] java.lang.NullPointerException
[error] 	at sbt.internal.librarymanagement.StringUtilities$.nonEmpty(StringUtilities.scala:15)
[error] 	at sbt.librarymanagement.DependencyBuilders$OrganizationArtifactName.$percent(DependencyBuilders.scala:53)
[error] 	at $ae12869c4301df8c73b7$.$sbtdef(/tmp/sbt_c4eaddbe/project/plugins.sbt:1)
[error] 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[error] 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
[error] 	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[error] 	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
[error] 	at sbt.compiler.Eval$.getValue(Eval.scala:587)
[error] 	at sbt.compiler.Eval.$anonfun$eval$1(Eval.scala:132)
[error] 	at sbt.internal.EvaluateConfigurations$.$anonfun$evaluateDslEntry$1(EvaluateConfigurations.scala:249)

[SethTisue]

serves me right for just YOLOing deleting project/Publish.scala in its entirety — turns out there was a baby in that bathwater:

scriptedLaunchOpts += version.apply { v => s"-Dproject.version=$v" }.value