💚 install typescript before test

Author: leeyeh

package.json

@@ -51,7 +51,7 @@
     "email": "support@leancloud.rocks"
   },
   "scripts": {
-    "test": "npm install --no-save leancloud-storage@3 && npm-run-all test-tsd test-express test-koa1 test-koa2",
+    "test": "npm install --no-save leancloud-storage@3 typescript@2 && npm-run-all test-tsd test-express test-koa1 test-koa2",
     "test-express": "mocha test test/express",
     "test-tsd": "tsc leanengine.d.ts",
     "test-koa1": "npm install --no-save leancloud-storage@3 koa@1 koa-bodyparser@2 && env FRAMEWORK=koa KOA_VER=1 mocha test test/koa",