function "get_anlz_factor" return error

[xx565763914]

description: with pandas version: 1.3.4，there is a error when calling get_anlz_factor，which result in calling error when invoke function anlzd_stdev and sharpe_ratio

problem reason: at function get_anlz_factor，the map PERIODS_PER_YEAR doesn't has correct key type int，it's FreqGroup.FR_ANN at pandas 1.3.4

possible solution: use FreqGroup.value to get correction key.