Lock webpack version to 5.76.1

This is a strict requirement of `@angular-devkit/build-angular` 15.2.5

Specifying the version as `@^5.0.0` causes multiple versions to be installed side by side, which leads to build issues.
Adding this "exact version dependency" gets rid of the warning but does not change yarn.lock (because that same version was already being resolved)

Author: ybnd

package.json

@@ -199,6 +199,7 @@
     "sass-resources-loader": "^2.2.5",
     "ts-node": "^8.10.2",
     "typescript": "~4.8.4",
+    "webpack": "5.76.1",
     "webpack-bundle-analyzer": "^4.8.0",
     "webpack-cli": "^4.2.0",
     "webpack-dev-server": "^4.13.3"