Cache configuration checks should consider negative values for NumCounters/MaxCost/BufferItems

[ankon]

Found while reading through the code:
https://github.com/dgraph-io/ristretto/blob/c67e07994f911dbf42104f568c83a29830e88236/cache.go#L169-L174

The checks are fine, but given that these are int64s they could be <0 which the checks won't catch unless I'm missing something.

[github-actions]

This issue has been stale for 60 days and will be closed automatically in 7 days. Comment to keep it open.

[zhaohaihang]

I also think that the aforementioned variables should be set to be greater than 0. Because if the aforementioned variables are less than 0, it will cause the program to fail. Since we're already performing checks, why not do it even better?

[mangalaman93]

Fixed by #410