Revert "Add VietName lunar calendar"

README.md

@@ -1357,8 +1357,7 @@ The following calendars are supported
 
 * [Chinese Lunar](./calendar/lunar/README.md "Chinese Lunar")：contributed
   by [gouguoyin](https://github.com/gouguoyin "gouguoyin")
-* [Vietnamese Lunar](./calendar/vlunar/README.md "Vietnamese Lunar")：contributed
-  by [culy247](https://github.com/culy247 "culy247")
+
 ##### I18n
 
 The following languages are supported

calendar.go

@@ -2,7 +2,6 @@ package carbon
 
 import (
 	"github.com/golang-module/carbon/v2/calendar/lunar"
-	"github.com/golang-module/carbon/v2/calendar/vlunar"
 )
 
 // Lunar converts gregorian calendar to lunar calendar.
@@ -22,21 +21,3 @@ func CreateFromLunar(year, month, day, hour, minute, second int, isLeapMonth boo
 	c.time = lunar.NewLunar(year, month, day, hour, minute, second, isLeapMonth).ToGregorian().Time
 	return c
 }
-
-// Lunar converts the solar calendar to the lunar calendar.
-// 将公历转为农历
-func (c Carbon) VLunar() (l vlunar.Lunar) {
-	if c.Error != nil {
-		l.Error = c.Error
-		return l
-	}
-	return vlunar.NewGregorian(c.ToStdTime()).ToLunar()
-}
-
-// CreateFromLunar creates a Carbon instance from Lunar date and time.
-// 从 农历日期 创建 Carbon 实例
-func CreateFromVLunar(year, month, day, hour, minute, second int, isLeapMonth bool) Carbon {
-	c := NewCarbon()
-	c.time = vlunar.NewLunar(year, month, day, hour, minute, second, isLeapMonth).ToGregorian().Time
-	return c
-}