[ci skip] Update project version to 2.0.0.

Bumped version from 1.2.3 to 2.0.0 to reflect major updates or breaking changes in the codebase. Ensure all dependencies and documentation align with the new versioning. This change is crucial for proper version tracking and release management.

version-checker/build.gradle.kts

@@ -15,7 +15,7 @@ tasks.compileJava {
 }
 
 group = "net.thenextlvl.core"
-version = "1.2.3"
+version = "2.0.0"
 
 repositories {
     mavenCentral()