Release 2.6.0 (#139)

* Update pom.xml

* BentoBox 2.0.0 API

* Updated Github Build Action

* Avoid potential error if island owner is null

User.getInstance(island.getOwner());

* Added initial test class for StoneGeneratorManager.

Refactored some code to not use Optional as a method parameter.

* Added tests.

* Try org.apache.commonscommons-lang3 to compile

* Upgrade to BentoBox 2.0.0 and Spigot 1.20

* Update to 1.20.4

* Update BentoBox 2.0.0 API for RanksManager

* Update TIPPED ARROW to use Spigot API in panels

* Update to Java 21

* Fix project key

* Validate island data once owner is changed

Add TeamSetownerEvent that validates unlocked generatrs once owner is changed.

* Return the Pladdon that was made.

* Only register IslandLevelListener if Level addon is present (#134)

* Update to 1.21.3 and CodeMC (#138)

* Update to 1.21.3 and CodeMC

* Fix typo

* Update versions in POM

* Update POM, fix JavaDoc

* Update POM

* Update maven-compiler-plugin

---------

Co-authored-by: BONNe <[email protected]>
Co-authored-by: IAISI <[email protected]>