Bump node-fetch from 2.6.0 to 2.6.7 in /api

Bumps [node-fetch](https://github.com/node-fetch/node-fetch) from 2.6.0 to 2.6.7.
- [Release notes](https://github.com/node-fetch/node-fetch/releases)
- [Commits](node-fetch/node-fetch@v2.6.0...v2.6.7)

---
updated-dependencies:
- dependency-name: node-fetch
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

api/package-lock.json

@@ -66,7 +66,7 @@
     "koa-static": "^5.0.0",
     "mocha": "^6.0.2",
     "njwt": "^1.0.0",
-    "node-fetch": "^2.3.0",
+    "node-fetch": "^2.6.7",
     "nodemon": "^1.18.10",
     "nyc": "^13.3.0",
     "pg": "^7.8.2",