These upgrades were prompted by guardian/atom-maker#94,
but they're all a good idea anyway:

* Play: 2.8 → 2.9
* Scala: 2.12 → 2.13
* Java: 8 → 11

https://www.playframework.com/documentation/2.9.x/ApplicationSecret

Note that as atom-workshop currently doesn't _use_ the PLAY_SESSION
cookie for anything (mainly because it uses
https://github.com/guardian/pan-domain-authentication for authentication)
it's probably okay for play.http.secret.key to _not_ be secret (which it
isn't, being in this public repo) - but it _does_ need to be long enough
to satisfy the Playframework and JJWT:

playframework/playframework#10726

If atom-workshop ever _does_ use the PLAY_SESSION cookie, it should
adopt https://github.com/guardian/play-secret-rotation to stay secure.

Prompted by this error message in the logs:

application.conf @ file:/usr/share/atom-workshop/conf/application.conf: 9: parsers.text.maxLength is deprecated, use play.http.parser.maxMemoryBuffer instead

Apparently the parsers.text.maxLength property has been deprecated since
Play 2.4 and playframework/playframework#4093

https://www.playframework.com/documentation/2.9.x/ScalaBodyParsers#Max-content-length

In atom-workshop, the increased size was set to allow bigger chart atoms:

#272

Prompted by this error in the logs:

Jan 26, 2024 @ 12:06:34.865	12:06:32,373 |-ERROR in ch.qos.logback.core.rolling.RollingFileAppender[FILE] - openFile(application.home_IS_UNDEFINED/logs/application.log,true) call failed. java.io.FileNotFoundException: application.home_IS_UNDEFINED/logs/application.log (No such file or directory)

See also:

* https://stackoverflow.com/a/47331903
* https://github.com/guardian/ophan/blob/2ecb80da40915ce097e4a1de0e29b352b396323e/dashboard/conf/logback.xml#L16-L19

Prompted by this in the logs:

Jan 26, 2024 @ 16:44:08.273	java.lang.NoSuchMethodError: 'void play.api.mvc.DiscardingCookie.<init>(java.lang.String, java.lang.String, scala.Option, boolean)'
Jan 26, 2024 @ 16:44:08.273		at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1020)
Jan 26, 2024 @ 16:44:08.273		at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1656
Jan 26, 2024 @ 16:44:08.271		at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(ForkJoinExecutorConfigurator.scala:48)
Jan 26, 2024 @ 16:44:08.271		at com.gu.pandomainauth.action.AuthActions.com$gu$pandomainauth$action$AuthActions$$discardCookies$(Actions.scala:102)

I had forgotten to update the version of Panda used - we're upgrading
to Play 2.9, so we need pan-domain-auth-play_2-9.

I'm not sure why I set the CI Java version to 17 (other than I have
started using that Java version elsewhere) - but as the AMI is only
`editorial-tools-focal-java11-ARM-WITH-cdk-base`, when the server
tried to run code that had been compiled with Java 17, it gave an
UnsupportedClassVersionError like this in the logs:

play.api.UnexpectedException: Unexpected exception[RuntimeException: java.lang.UnsupportedClassVersionError: controllers/routes has been compiled by a more recent version of the Java Runtime (class file version 61.0), this version of the Java Runtime only recognizes class file versions up to 55.0]
	at play.api.http.HttpErrorHandlerExceptions$.throwableToUsefulException(HttpErrorHandler.scala:384)