Base64 does not support url_safe codec

[det101]

Base64 does not support url_safe codec, resulting in inconsistencies with the backend
example：

secret key = "u-rXsMB_aegAnzC_CJt27plLGNqOfR2EHI5o2ro1NOI";
message = "https://github.com/";

var hash = CryptoJS.HmacSHA256(message, baseKey);
var hashInBase64 = CryptoJS.enc.Base64.stringify(hash);

Expect the results: KkcD0POQJ50q-NsUoOwsrrc8140TYEtfiQBCwbf0u04
The actual results: KkcD0POQJ50q+NsUoOwsrrc8140TYEtfiQBCwbf0u04=