fix: Explicitly declare accpet type to json when exchanging oauth token (#801)

Author: JoJoJoJoJoJoJo

src/client/auth.ts

@@ -774,6 +774,7 @@ export async function exchangeAuthorization(
   // Exchange code for tokens
   const headers = new Headers({
     "Content-Type": "application/x-www-form-urlencoded",
+    "Accept": "application/json",
   });
   const params = new URLSearchParams({
     grant_type: grantType,