Fix failing test import for xlsx

Author: risenW

src/danfojs-browser/package.json

@@ -31,7 +31,7 @@
   },
   "scripts": {
     "test": "karma start --single-run --browsers ChromeHeadless karma.conf.js",
-    "test:clean": "yarn build:clean && yarn run test",
+    "test:clean": "yarn build:clean && yarn add xlsx@0.17.2 -P && yarn run test",
     "build": "node ./scripts/prebuild.js && tsc && yarn run bundle",
     "build:clean": "rimraf ./dist && rimraf ./lib && node ./scripts/prebuild.js && yarn run build",
     "dev": "nodemon",