Update tabbable and focus-trap dependencies in focus plugin

Update `tabbable` from ^5.3.3 to ^6.4.0 and `focus-trap` from ^6.9.4 to ^8.0.0.

These packages only support their most recently published version, so staying
on older versions means no security patches. This addresses concerns raised
in governmental security audits.

Breaking changes in these packages (IE support dropped, displayCheck defaults)
do not affect Alpine's usage patterns.

Author: joshhanley

package-lock.json

@@ -14,7 +14,7 @@
     "module": "dist/module.esm.js",
     "unpkg": "dist/cdn.min.js",
     "dependencies": {
-        "focus-trap": "^6.9.4",
-        "tabbable": "^5.3.3"
+        "focus-trap": "^8.0.0",
+        "tabbable": "^6.4.0"
     }
 }