fix(package): update dotenv to version 8.0.0

Closes #116

Author: greenkeeper[bot]

package.json

@@ -38,7 +38,7 @@
     "cookie-parser": "^1.4.3",
     "cors": "^2.8.4",
     "debug": "^3.1.0",
-    "dotenv": "^6.0.0",
+    "dotenv": "^8.0.0",
     "express": "^4.16.2",
     "express-handlebars": "^3.0.0",
     "imgur": "^0.2.1",