Release v5.2.3

• (@GermanBluefox) When the server rejects the access token (reauthenticate), the connection first tries to get a new one with the refresh token and only goes to the login page if that fails. Until now every reauthenticate led to the login page, although the user had asked to stay logged in
• (@GermanBluefox) A failed token refresh no longer throws the tokens away when another tab has renewed them in the meantime (a refresh token can be used only once); the new access token is announced to the server instead. Tokens are only deleted when the server has really rejected the refresh token, a server that cannot be reached leads to a retry
• (@GermanBluefox) Only one refresh request runs at a time, and waiting for the lock of another tab no longer spins synchronously