consider truncate large write rather than throw error

[shiyuhang0]

An error will throw when the write size is larger than the max file size.

you can check the code here

lumberjack/lumberjack.go

Line 142 in 4cb27fc

"write length %d exceeds maximum file size %d", writeLen, l.max(),

Is it acceptable to add a truncate option to truncate the writes? I can contribute if it is accepted.