build: bump gradle 6.8.2 -> 8.2.1

[jdrueckert]

Relates to MovingBlocks/Terasology#5109
Relates to MovingBlocks/Terasology#4653

Contains

• Updating gradle from 6.8.2 -> 8.2.1
• Updating gradle's files for which became invalid

How to test

• run gradlew build -> do we build JNLua this way?
• we could further test it in combination with Terasology (groovyw lib get JNLua && gradlew jar game)

Remarks

Java 20 is not yet supported, see gradle/gradle#23488.

[rosti-il]

Updating gradle from 6.8.2 -> 8.2

Why not 8.2.1?

[skaldarnar]

I noticed that JNLua is not picked up as a lib when fetched via groovyw lib get JNLua. The repo is cloned to the libs/ folder, but it does not show up as a (sub-)project:

❯ gradlew projects

------------------------------------------------------------
Root project 'Terasology'
------------------------------------------------------------

Root project 'Terasology'
+--- Project ':engine'
+--- Project ':engine-tests'
+--- Project ':facades'
|    \--- Project ':facades:PC'
+--- Project ':libs'
+--- Project ':metas'
+--- Project ':modules'
|    +--- Project ':modules:BiomesAPI'
|    +--- Project ':modules:CoreAdvancedAssets'
|    +--- Project ':modules:CoreAssets'
|    +--- Project ':modules:CoreRendering'
|    +--- Project ':modules:CoreSampleGameplay'
|    +--- Project ':modules:CoreWorlds'
|    +--- Project ':modules:Drops'
|    +--- Project ':modules:Explosives'
|    +--- Project ':modules:Furnishings'
|    +--- Project ':modules:Health'
|    \--- Project ':modules:Inventory'
\--- Project ':subsystems'
     +--- Project ':subsystems:DiscordRPC'
     \--- Project ':subsystems:TypeHandlerLibrary'

When trying to run the build directly in libs/JNLua I get the following error:

Project directory '/home/skaldarnar/Code/movingblocks/ts-iota/libs/JNLua' is not part of the build defined by settings file '/home/skaldarnar/Code/movingblocks/ts-iota/settings.gradle'. If this is an unrelated build, it must have its own settings file.

In a stand-alone clone of this repo gradlew build succeeds just fine:

❯ gradlew build

BUILD SUCCESSFUL in 554ms
6 actionable tasks: 6 up-to-date

Running tests fails on both master and this PR, though.

The README mentions some "Jenkins magic" to build and publish artifacts, as well as a manual step to run on @Cervator 's MacBook. Since we're not changing anything in the lib itself, I would just merge this upgrade to Gradle, assuming that everything works the same as before. The Gradle build files are simple enough, I don't expect any features to break in the Gradlew upgrade.

LGTM