fix: examples/custom-webpack/sanity-app/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-ONHEADERS-10773729

Author: snyk-io[bot]

examples/custom-webpack/sanity-app/package.json

@@ -25,7 +25,7 @@
     "zone.js": "0.14.7"
   },
   "devDependencies": {
-    "@angular-builders/custom-webpack": "workspace:*",
+    "@angular-builders/custom-webpack": "2.2.0",
     "@angular-devkit/build-angular": "18.0.1",
     "@angular/cli": "18.0.1",
     "@angular/compiler-cli": "18.0.6",