Update the ovsx dev dependency to 0.9

Author: remcohaszing

packages/vscode-mdx/package.json

@@ -45,7 +45,7 @@
     "@volar/vscode": "~2.2.0",
     "@vscode/vsce": "^2.0.0",
     "esbuild": "^0.20.0",
-    "ovsx": "^0.8.0"
+    "ovsx": "^0.9.0"
   },
   "galleryBanner": {
     "color": "#fcb32c",