fix signing key issue

Author: thdxr

packages/openauth/src/issuer.ts

@@ -1118,7 +1118,7 @@ export function issuer<
       mode: "access"
       type: keyof SubjectSchema
       properties: v1.InferInput<SubjectSchema[keyof SubjectSchema]>
-    }>(token, () => signingKey.then((item) => item.public), {
+    }>(token, () => signingKey().then((item) => item.public), {
       issuer: issuer(c),
     })