Flagger v1.20.0

Changes

• +AppMesh: Add annotation to enable Envoy access logsadded
• +Contour: Update the httproxy API and enable RetryOnadded
• +Istio: Add destination port when port discovery and delegation are trueadded
• +Metrics: Add canary analysis result as Prometheus metricsadded
• *Fix canary rollback behaviourfixed
• *Shorten the metric analysis cycle after confirm promotion gate is openfixed
• *Fix unit of time in the Istio Grafana dashboardfixed
• *Fix the service toggle condition in the podinfo helm chartfixed