feat: update angular and add rxjs dependency

Upgrade Angular peer dependencies to v20.1.x. Add rxjs v7.8.0.

Author: joh-klein

libs/ngx-blocknote/package.json

@@ -13,14 +13,15 @@
     "@ng-icons/lucide": ">=29.0.0",
     "@spartan-ng/brain": "^0.0.1-alpha.445",
     "class-variance-authority": "^0.7.0",
-    "clsx": "^2.1.1"
+    "clsx": "^2.1.1",
+    "rxjs": "~7.8.0"
   },
   "devDependencies": {},
   "peerDependencies": {
-    "@angular/core": "~19.2.0",
-    "@angular/common": "~19.2.0",
-    "@angular/forms": "~19.2.0",
-    "@angular/cdk": "~19.2.0"
+    "@angular/core": "20.1.6",
+    "@angular/common": "20.1.6",
+    "@angular/forms": "20.1.6",
+    "@angular/cdk": "20.1.5"
   },
   "peerDependenciesMeta": {
     "@angular/platform-browser": {