fix: add @types/when to the optional dependencies due to .d.ts files

Author: aminya

package.json

@@ -82,13 +82,15 @@
     "node-wget-fetch": "^1.1.3",
     "when": "^3.7.8"
   },
+  "optionalDependencies": {
+      "@types/when": "^2.4.34"
+  },
   "devDependencies": {
     "@types/chai": "^4.3.3",
     "@types/fs-extra": "^9.0.13",
     "@types/minimist": "1.2.2",
     "@types/mocha": "^9.1.1",
     "@types/node": "^18.7.12",
-    "@types/when": "^2.4.34",
     "chai": "^4.3.6",
     "mocha": "^10.0.0",
     "typescript": "^4.7.4"