Update y.go

[pic4xiu]

If the mask entered by the user is greater than 32, it will return empty when calling net's CIDRMask, causing a panic when the program continues

❯ go run main.go
panic: runtime error: index out of range [3] with length 0

goroutine 1 [running]:
encoding/binary.bigEndian.Uint32(...)
        /usr/local/go/src/encoding/binary/binary.go:157
github.com/malfunkt/iprange.(*ipParserImpl).Parse(0x1400012e000, {0x1049143c8?, 0x14000120050?})
        yaccpar:351 +0x14bc
github.com/malfunkt/iprange.ipParse(...)
        yaccpar:153
github.com/malfunkt/iprange.ParseList({0x1048d3770?, 0x140000021a0?})
        ip.y:93 +0xa0
main.main()
        /Users/*/Desktop/sensor/bigdata/waf2/main.go:10 +0x28
exit status 2

I made a judgment after calling CIDRMask to generate the mask, and let it be limited to 32, so that when the user enters a value greater than 32, it will be automatically judged as 32. In this way, the program can avoid panic