chore(deps-dev): bump @types/big.js from 6.1.2 to 6.2.0

Bumps [@types/big.js](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/big.js) from 6.1.2 to 6.2.0.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/big.js)

---
updated-dependencies:
- dependency-name: "@types/big.js"
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

package.json

@@ -66,7 +66,7 @@
   },
   "devDependencies": {
     "@polkadot/typegen": "9.14.2",
-    "@types/big.js": "6.1.2",
+    "@types/big.js": "6.2.0",
     "@types/chai": "^4.2.12",
     "@types/chai-as-promised": "^7.1.3",
     "@types/mocha": "^10.0.1",