tests: Fix StubServer

worldedit-bukkit/src/test/java/com/fastasyncworldedit/util/StubServer.java

@@ -49,6 +49,7 @@ import org.bukkit.plugin.Plugin;
 import org.bukkit.plugin.PluginManager;
 import org.bukkit.plugin.ServicesManager;
 import org.bukkit.plugin.messaging.Messenger;
+import org.bukkit.potion.PotionBrewer;
 import org.bukkit.scheduler.BukkitScheduler;
 import org.bukkit.scoreboard.ScoreboardManager;
 import org.bukkit.structure.StructureManager;
@@ -1078,6 +1079,11 @@ public class StubServer implements Server {
         return null;
     }
 
+    @Override
+    public @NotNull PotionBrewer getPotionBrewer() {
+        return null;
+    }
+
     @Override
     public @NotNull
     Iterable<? extends Audience> audiences() {