fix(deps): update dependency com.github.seeseemelk:mockbukkit-v1.20 to v3.89.0

Author: renovate[bot]

gradle/libs.versions.toml

@@ -11,7 +11,7 @@ shadow = "8.1.1"
 # Libraries
 spigot8 = "1.8.8-R0.1-SNAPSHOT"
 spigotLatest = "1.20.2-experimental-SNAPSHOT"
-mockBukkit = "3.78.0"
+mockBukkit = "3.89.0"
 
 [plugins]
 kotlin-jvm = { id = "org.jetbrains.kotlin.jvm", version.ref = "kotlin" }