ParseByFormat()方法部分情况下无效

[open-git]

carbon.ParseByFormat("It is 2020-08-05 13:14:15", "It is Y-m-d H:i:s").ToDateTimeString()输出空，错误信息

the value "It is 2020-08-05 13:14:15" can't parse string as carbon

[180909]

感觉跟这个issue一样，#56

[open-git]

改成carbon.ParseByFormat("It is 2020-08-05 13:14:15", "\I\t \i\s Y-m-d H:i:s").ToDateTimeString()也是输出空

[gouguoyin]

改成carbon.ParseByFormat("It is 2020-08-05 13:14:15", "\I\t \i\s Y-m-d H:i:s").ToDateTimeString()也是输出空

v1.4.3版本已修复