Update dependency dotenv to v16.4.6

Author: renovate[bot]

package.json

@@ -49,7 +49,7 @@
   "devDependencies": {
     "ava": "4.0.1",
     "coveralls": "3.1.1",
-    "dotenv": "16.0.0",
+    "dotenv": "16.4.6",
     "nyc": "15.1.0",
     "standard": "16.0.4"
   },