refactor: modernize the sample tests (#173)

Author: JustinBeckwith

packages/google-cloud-videointelligence/samples/package.json

@@ -1,6 +1,5 @@
 {
   "name": "nodejs-docs-samples-videointelligence",
-  "version": "0.0.1",
   "private": true,
   "license": "Apache-2.0",
   "files": [
@@ -13,14 +12,15 @@
     "node": ">=8"
   },
   "scripts": {
-    "test": "mocha system-test/*.test.js --timeout=600000"
+    "test": "mocha system-test --timeout=600000"
   },
   "dependencies": {
     "@google-cloud/video-intelligence": "^1.5.0",
     "yargs": "^12.0.0"
   },
   "devDependencies": {
-    "@google-cloud/nodejs-repo-tools": "^3.0.0",
-    "ava": "^0.25.0"
+    "chai": "^4.2.0",
+    "execa": "^1.0.0",
+    "mocha": "^5.2.0"
   }
 }