Request a new access token from the backend. A valid refresh token must be passed as an argument or through the `Authorization` HTTP header (with the `Bearer` scheme).
POST /auth/refresh?rt=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJTYW1vdXJhaSBXYWxsZXQgYmFja2VuZCIsInR5cGUiOiJyZWZyZXNoLXRva2VuIiwiaWF0IjoxNTQ0MTAzOTI5LCJleHAiOjE1NDQxMTExMjl9.6gykKq31WL4Jq7hfmoTwi1fpmBTtAeFb4KjfmSO6l00