fix autofilter range

cmd/main/main.go

@@ -151,7 +151,7 @@ func main() {
 
 	// Handle autofilter
 	if autoFilter {
-		// cell is still a reference to the last cell in the header row
+		cell, _ = excelize.CoordinatesToCellName(len(columnNames), 1)
 		filterRange := "A1:" + cell
 		fmt.Printf("Setting autofilter to range '%s'\n", filterRange)
 		// As per docs any filters applied need to be manually processed by us (eg hiding rows with blanks)