fix(deps): update dependency ngx-markdown to v20

Author: renovate[bot]

package.json

@@ -25,7 +25,7 @@
     "@angular/platform-browser-dynamic": "20.0.0",
     "@angular/router": "20.0.0",
     "marked": "^15.0.11",
-    "ngx-markdown": "^19.1.1",
+    "ngx-markdown": "^20.0.0",
     "prismjs": "^1.30.0",
     "rxjs": "~7.8.2",
     "tslib": "^2.8.1",