internal/triage/priority: add missing WITHDRAWN case in state function

Change-Id: Ic50c5ff02d25a08d6d4950925a203a1c5eafff4c
Reviewed-on: https://go-review.googlesource.com/c/vulndb/+/609598
Reviewed-by: Damien Neil <dneil@google.com>
Auto-Submit: Tatiana Bradley <tatianabradley@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

internal/triage/priority/priority.go

@@ -158,7 +158,8 @@ func state(r *report.Report) reportState {
 			report.ExcludedLegacyFalsePositive:
 			return excludedBinary
 		case report.ExcludedNotAVulnerability,
-			report.ExcludedDependentVulnerabilty:
+			report.ExcludedDependentVulnerabilty,
+			report.ExcludedWithdrawn:
 			return excludedOther
 		default:
 			return unknownReportState