feat: Provide time.Parse and time.Now while evaluating trigger condition

Similar to argocd:
- https://github.com/argoproj-labs/argocd-notifications/pull/22/files#diff-5b3e361e78e62137bc7f887d765e7c4bfbb85e01685b6640c41d74118d3e2f7dR11-R28
- https://argo-cd.readthedocs.io/en/stable/operator-manual/notifications/triggers/#functions

utils/record/record.go

@@ -230,7 +230,7 @@ func NewAPIFactorySettings() api.Settings {
 		ConfigMapName: NotificationConfigMap,
 		InitGetVars: func(cfg *api.Config, configMap *corev1.ConfigMap, secret *corev1.Secret) (api.GetVars, error) {
 			return func(obj map[string]interface{}, dest services.Destination) map[string]interface{} {
-				return map[string]interface{}{"rollout": obj}
+				return map[string]interface{}{"rollout": obj, "time": newTimeExprs()}
 			}, nil
 		},
 	}
@@ -353,3 +353,22 @@ func translateReasonToTrigger(reason string) string {
 	trigger = matchAllCap.ReplaceAllString(trigger, "${1}-${2}")
 	return "on-" + strings.ToLower(trigger)
 }
+
+func newTimeExprs() map[string]interface{} {
+	return map[string]interface{}{
+		"Parse": parse,
+		"Now":   now,
+	}
+}
+
+func parse(timestamp string) time.Time {
+	res, err := time.Parse(time.RFC3339, timestamp)
+	if err != nil {
+		panic(err)
+	}
+	return res
+}
+
+func now() time.Time {
+	return time.Now()
+}