Fix namespace when calling some global functions in readme (#34)

README.md

@@ -75,25 +75,25 @@ gron.BatchDue(exprs, ref)
 To find out when is the cron due next (in near future):
 ```go
 allowCurrent = true // includes current time as well
-nextTime, err := gron.NextTick(expr, allowCurrent) // gives time.Time, error
+nextTime, err := gronx.NextTick(expr, allowCurrent) // gives time.Time, error
 
 // OR, next tick after certain reference time
 refTime = time.Date(2022, time.November, 1, 1, 1, 0, 0, time.UTC)
 allowCurrent = false // excludes the ref time
-nextTime, err := gron.NextTickAfter(expr, refTime, allowCurrent) // gives time.Time, error
+nextTime, err := gronx.NextTickAfter(expr, refTime, allowCurrent) // gives time.Time, error
 ```
 
 ### Prev Tick
 
 To find out when was the cron due previously (in near past):
 ```go
 allowCurrent = true // includes current time as well
-prevTime, err := gron.PrevTick(expr, allowCurrent) // gives time.Time, error
+prevTime, err := gronx.PrevTick(expr, allowCurrent) // gives time.Time, error
 
 // OR, prev tick before certain reference time
 refTime = time.Date(2022, time.November, 1, 1, 1, 0, 0, time.UTC)
 allowCurrent = false // excludes the ref time
-nextTime, err := gron.PrevTickBefore(expr, refTime, allowCurrent) // gives time.Time, error
+nextTime, err := gronx.PrevTickBefore(expr, refTime, allowCurrent) // gives time.Time, error
 ```
 
 > The working of `PrevTick*()` and `NextTick*()` are mostly the same except the direction.