Excelize: Negative shared-string index causes panic in GetCellValue and GetRows

Excelize is a Go language library for reading and writing Microsoft Excel spreadsheets. Prior to 2.11.0, Excelize parses shared-string cell values with strconv.Atoi and checks only the upper bound before indexing the shared string slice, allowing an XLSX file containing a shared-string cell with -1 to trigger sharedStrings[-1] and panic when read through GetCellValue or GetRows. This issue is fixed in version 2.11.0.