fix: upgrade form-data from 2.3.3 to 2.5.1 (#22)

Snyk has created this PR to upgrade form-data from 2.3.3 to 2.5.1.

See this package in npm:
https://www.npmjs.com/package/form-data

See this project in Snyk:
https://app.snyk.io/org/davehorton/project/b7e09765-19b2-4aa5-90ba-10432e250041?utm_source=github&utm_medium=referral&page=upgrade-pr

package.json

@@ -28,7 +28,7 @@
     "cors": "^2.8.5",
     "debug": "^4.3.3",
     "express": "^4.17.1",
-    "form-data": "^2.3.3",
+    "form-data": "^2.5.1",
     "form-urlencoded": "^6.0.4",
     "jsonwebtoken": "^8.5.1",
     "mailgun.js": "^3.7.3",