fix(package): update dotenv to version 7.0.0

Author: greenkeeper[bot]

examples/simple-bot/package.json

@@ -9,7 +9,7 @@
   "license": "Apache-2.0",
   "dependencies": {
     "botkit": "^0.7.2",
-    "dotenv": "^6.0.0",
+    "dotenv": "^7.0.0",
     "express": "^4.16.3",
     "botkit-middleware-watson": "^1.7.1"
   }