Replace usage of log.warning with log.warn

src/virtual-machine.js

@@ -653,7 +653,7 @@ class VirtualMachine extends EventEmitter {
      * @returns {Promise} Promise that resolves after the project has loaded
      */
     fromJSON (json) {
-        log.warning('fromJSON is now just a wrapper around loadProject, please use that function instead.');
+        log.warn('fromJSON is now just a wrapper around loadProject, please use that function instead.');
         return this.loadProject(json);
     }