Upgrade the minimum Java version

[gbrail]

I have in the past been adamant that we maintain Java 8 compatibility in this project, but with all the changes going into Java today, that's getting increasingly difficult -- right now it's a lot of work to have a project that builds with both Java 8 and Java 20, for example. Large organizations seem to be deploying Java 17 pretty broadly, for example, so I think that policies that were holding people on Java 8 may be gone by now.

Given all that, what Java version does the community think that we should be targetting? I could see easily going up to Java 11, for example, but there are additional advantages to supporting even newer versions.

[p-bakker]

Better move this to discussions? We already have somewhat of a discussion going there: #1169

Having said that, from my perspective moving to 11 or even 17 is fine.

Not sure what is desired from the perspective of running Rhino on Android

[p-bakker]

As of the merge of #1479 the minimum Java version for Rhino is 11