fix: package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-NODEFETCH-674311

Author: snyk-bot

package.json

@@ -71,7 +71,7 @@
     ]
   },
   "dependencies": {
-    "isomorphic-fetch": "2.2.1",
+    "isomorphic-fetch": "3.0.0",
     "lodash.get": "4.4.2",
     "xml2js": "0.4.17"
   }