Add mysql clear password

Author: r0mant

client/auth.go

@@ -116,6 +116,8 @@ func (c *Conn) genAuthResponse(authData []byte) ([]byte, bool, error) {
 		return CalcPassword(authData[:20], []byte(c.password)), false, nil
 	case AUTH_CACHING_SHA2_PASSWORD:
 		return CalcCachingSha2Password(authData, c.password), false, nil
+	case AUTH_CLEAR_PASSWORD:
+		return []byte(c.password), true, nil
 	case AUTH_SHA256_PASSWORD:
 		if len(c.password) == 0 {
 			return nil, true, nil

mysql/const.go

@@ -22,6 +22,7 @@ const (
 	AUTH_NATIVE_PASSWORD       = "mysql_native_password"
 	AUTH_CACHING_SHA2_PASSWORD = "caching_sha2_password"
 	AUTH_SHA256_PASSWORD       = "sha256_password"
+	AUTH_CLEAR_PASSWORD        = "mysql_clear_password"
 )
 
 const (