feat(report) : Differences between vulnerability patched items (#1157)

* add plusDiff() and minusDiff()
* add plusDiff minusDiff test

Co-authored-by: Kota Kanbe <kotakanbe@gmail.com>

report/tui.go

@@ -633,6 +633,7 @@ func summaryLines(r models.ScanResult) string {
 		var cols []string
 		cols = []string{
 			fmt.Sprintf(indexFormat, i+1),
+			string(vinfo.DiffStatus),
 			vinfo.CveID,
 			cvssScore + " |",
 			fmt.Sprintf("%-6s |", av),