chore(deps): update angular-cli monorepo to v21

Author: renovate[bot]

package.json

@@ -33,8 +33,8 @@
     "zone.js": "~0.15.0"
   },
   "devDependencies": {
-    "@angular/build": "^20.1.2",
-    "@angular/cli": "^20.1.2",
+    "@angular/build": "^21.0.0",
+    "@angular/cli": "^21.0.0",
     "@angular/compiler-cli": "^20.1.3",
     "@schedule-x/calendar": "3.3.0",
     "@schedule-x/drag-and-drop": "^3.3.0",