fix(deps): update @portabletext/toolkit v2.0.17 (#195)

Fixes error when `markDefs` is null in `buildMarksTree` function. Tested locally.

Author: theisel

astro-portabletext/package.json

@@ -48,7 +48,7 @@
     "check": "astro check --root components"
   },
   "dependencies": {
-    "@portabletext/toolkit": "^2.0.16",
+    "@portabletext/toolkit": "^2.0.17",
     "@portabletext/types": "^2.0.13"
   },
   "peerDependencies": {