Convert to plugin so that legacy Materials are not used

src/main/java/com/wasteofplastic/invswitcher/InvSwitcherPladdon.java

@@ -0,0 +1,19 @@
+package com.wasteofplastic.invswitcher;
+
+
+import world.bentobox.bentobox.api.addons.Addon;
+import world.bentobox.bentobox.api.addons.GameModeAddon;
+import world.bentobox.bentobox.api.addons.Pladdon;
+
+public class InvSwitcherPladdon extends Pladdon {
+
+    private Addon addon;
+
+    @Override
+    public Addon getAddon() {
+        if (addon == null) {
+            addon = new InvSwitcher();
+        }
+        return addon;
+    }
+}

src/main/resources/plugin.yml

@@ -0,0 +1,9 @@
+name: BentoBox-InvSwitcher
+main: com.wasteofplastic.invswitcher.InvSwitcherPladdon 
+version: ${project.version}${build.number}
+api-version: "1.21"
+
+authors: [tastybento]
+contributors: ["The BentoBoxWorld Community"]
+website: https://bentobox.world
+description: ${project.description}