isSameMonth(date: BikramSambat): boolean
Returns true if the provided Bikram Sambat date has the same year and month as the current date.
const date1 = new BikramSambat('2078-05-15')
const date2 = new BikramSambat('2078-04-15')
const isSameMonth = date1.isSameMonth(date2) // true