Switch to Yarn for CI build. (#290)

Author: jmdobry

handwritten/datastore/samples/package.json

@@ -5,11 +5,11 @@
   "license": "Apache Version 2.0",
   "author": "Google Inc.",
   "scripts": {
-    "test": "cd ..; npm run st -- datastore/system-test/*.test.js"
+    "test": "cd ..; npm run st -- --verbose datastore/system-test/*.test.js"
   },
   "dependencies": {
     "@google-cloud/datastore": "0.6.0",
-    "yargs": "6.5.0"
+    "yargs": "6.6.0"
   },
   "engines": {
     "node": ">=4.3.2"