fix: use dotenv v5 to maintain node 4.x compatibility

Author: dpopp07

package-lock.json

@@ -83,7 +83,7 @@
     "async": "~2.6.1",
     "buffer-from": "~1.1.0",
     "csv-stringify": "~1.0.2",
-    "dotenv": "^6.2.0",
+    "dotenv": "^5.0.1",
     "extend": "~3.0.2",
     "file-type": "^7.7.1",
     "isstream": "~0.1.2",