fix: missing minecraft version in registry (#42)

Author: NgLoader

zip-common/src/main/java/net/imprex/zip/common/MinecraftVersion.java

@@ -19,6 +19,7 @@ private static final class NmsMapping {
 		private static final List<NmsMapping> MAPPINGS = new ArrayList<>();
 
 		static {
+			MAPPINGS.add(new NmsMapping("1.21.5", "v1_21_R4"));
 			MAPPINGS.add(new NmsMapping("1.21.4", "v1_21_R3"));
 			MAPPINGS.add(new NmsMapping("1.21.3", "v1_21_R2"));
 			MAPPINGS.add(new NmsMapping("1.21", "v1_21_R1"));