v0.4.0

Thanks to the following for their contributions:

• @nayyara-airlangga

Changed

• Make ticket validation request to be synchronous (#16) (@nayyara-airlangga)
• Rename ReqwestError to RequestError (#16) (@nayyara-airlangga)

Removed

• Remove tokio and replace reqwest with http_req (#16) (@nayyara-airlangga)