deps(dev): bump @types/formidable from 2.0.6 to 3.4.5

Bumps [@types/formidable](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/formidable) from 2.0.6 to 3.4.5.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/formidable)

---
updated-dependencies:
- dependency-name: "@types/formidable"
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

packages/it-multipart/package.json

@@ -132,7 +132,7 @@
     "it-pushable": "^3.2.0"
   },
   "devDependencies": {
-    "@types/formidable": "^2.0.5",
+    "@types/formidable": "^3.4.5",
     "aegir": "^41.1.9",
     "form-data": "^4.0.0",
     "it-drain": "^3.0.0",