Update MaterialLoader.js

Typo

src/loaders/MaterialLoader.js

@@ -180,6 +180,7 @@ MaterialLoader.prototype = Object.assign( Object.create( Loader.prototype ), {
 
 					case 'm3':
 						material.uniforms[ name ].value = new Matrix3().fromArray( uniform.value );
+						break;
 
 					case 'm4':
 						material.uniforms[ name ].value = new Matrix4().fromArray( uniform.value );