Lagom bundle causing deprecated crypto warning

[fsat]

Lagom bundle is causing deprecated crypto warning due to the -Dplay.crypto.secret system property set in bundle start command:

sbt-conductr/src/main/scala/com/lightbend/conductr/sbt/LagomBundlePlugin.scala

Lines 157 to 159 in efe3fb8

	// The application secret is not used by the Lagom project so the value doesn't really matter.
	// Therefore it is save to automatically generate one here. It is necessary though to set the key in prod mode.
	val applicationSecret = s"-Dplay.crypto.secret=${hash(s"${name.value}")}"

Important: before working on this fix, follow up the following Play issue:

playframework/playframework#8075

Basically the gist is Play should not enforce the crypto secret being mandatory unless it's actually used. In Lagom's case, the crypto secret is not used.

If relying the fix on Playframework's side, it may occur in Play >= 2.6.8, so a version detection will be necessary as Play <= 2.6.7 will continue to enforce the crypto secret being mandatory.