Update build.js

lib/build.js

@@ -47,7 +47,7 @@ const touchOverriddenVectorIconFiles = () => {
   // Return true when original file of |file| should be touched.
   const applyFileFilter = (file) => {
     // Only includes icon files.
-    return path.extname(file) === true
+    return path.extname(file) === '.icon'
   }
 
   const braveVectorIconsDir = path.join(config.srcDir, 'brave', 'vector_icons')