Align on usage of cross-fetch vs node-fetch in frontend vs backend packages

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

plugins/scaffolder-backend/package.json

@@ -50,7 +50,6 @@
     "command-exists": "^1.2.9",
     "compression": "^1.7.4",
     "cors": "^2.8.5",
-    "cross-fetch": "^3.0.6",
     "express": "^4.17.1",
     "express-promise-router": "^4.1.0",
     "fs-extra": "10.0.0",
@@ -65,6 +64,7 @@
     "lodash": "^4.17.21",
     "luxon": "^2.0.2",
     "morgan": "^1.10.0",
+    "node-fetch": "^2.6.1",
     "nunjucks": "^3.2.3",
     "octokit-plugin-create-pull-request": "^3.10.0",
     "uuid": "^8.2.0",