fix wrong type at ../collection/queryables

Author: MathewNWSH

stac_fastapi/core/stac_fastapi/core/models/links.py

@@ -139,7 +139,7 @@ def link_queryables(self) -> Dict[str, Any]:
         if "FilterExtension" in self.extensions:
             return dict(
                 rel="queryables",
-                type=MimeTypes.json.value,
+                type=MimeTypes.jsonschema.value,
                 href=urljoin(
                     self.base_url, f"collections/{self.collection_id}/queryables"
                 ),