Update dependency org.bukkit:bukkit to v1.15.2-R0.1-SNAPSHOT

Author: renovate[bot]

pom.xml

@@ -97,7 +97,7 @@
         <dependency>
             <groupId>org.bukkit</groupId>
             <artifactId>bukkit</artifactId>
-            <version>1.13-R0.1-SNAPSHOT</version>
+            <version>1.15.2-R0.1-SNAPSHOT</version>
         </dependency>
         <dependency>
             <groupId>org.bstats</groupId>