1.3.1 release notes (#5063)

* 1.1 release notes

* Cleaned up wording and formatting to match other point release

* Updated to remove UTF-8 from spelling as well as link to the last issue

* Moved release announcement to news

* Fixed capitalization and removed aliases for 1.3.1 release notes

* Removed references to pull requests rather than issues and added reference for metadata exchange and stats

* Added WebAssembly to the dictionary and removed duplicate of webhook

* Fixed date

.spelling

@@ -574,7 +574,7 @@ VPNs
 Warman
 WBoilerplates
 WeaveWorks
-webhook
+WebAssembly
 webhook
 Webhooks
 webhooks

content/en/news/2019/announcing-1.3.1/index.md

@@ -0,0 +1,32 @@
+---
+title: Announcing Istio 1.3.1
+description: Istio 1.3.1 release announcement.
+publishdate: 2019-09-27
+attribution: The Istio Team
+subtitle: Minor Update
+release: 1.3.1
+---
+
+This release includes bug fixes to improve robustness. This release note describes what’s different between Istio 1.3.0 and Istio 1.3.1.
+
+{{< relnote >}}
+
+## Bug fixes
+
+- **Fixed** an issue which caused the secret cleanup job to erroneously run during upgrades ([Issue 16873](https://github.com/istio/istio/issues/16873)).
+- **Fixed** an issue where the default configuration disabled Kubernetes Ingress support ([Issue 17148](https://github.com/istio/istio/issues/17148))
+- **Fixed** an issue with handling invalid `UTF-8` characters in the Stackdriver logging adapter ([Issue 16966](https://github.com/istio/istio/issues/16966)).
+- **Fixed** an issue which caused the `destination_service` label in HTTP metrics not to be set for `BlackHoleCluster` and `PassThroughCluster` ([Issue 16629](https://github.com/istio/istio/issues/16629)).
+- **Fixed** an issue with the `destination_service` label in the `istio_tcp_connections_closed_total` and `istio_tcp_connections_opened_total` metrics which caused them to not be set correctly ([Issue 17234](https://github.com/istio/istio/issues/17234)).
+- **Fixed** an Envoy crash introduced in Istio 1.2.4 ([Issue 16357](https://github.com/istio/istio/issues/16357)).
+- **Fixed** Istio CNI sidecar initialization when IPv6 is disabled on the node ([Issue 15895](https://github.com/istio/istio/issues/15895)).
+- **Fixed** a regression affecting support of RS384 and RS512 algorithms in JWTs ([Issue 15380](https://github.com/istio/istio/issues/15380)).
+
+## Minor enhancements
+
+- **Added** support for `.Values.global.priorityClassName` to the telemetry deployment.
+- **Added** annotations for Datadog tracing that controls extra features in sidecars.
+- **Added** the `pilot_xds_push_time` metric to report Pilot xDS push time.
+- **Added** `istioctl experimental analyze` to support multi-resource analysis and validation.
+- **Added** support for running metadata exchange and stats extensions in a WebAssembly sandbox. Follow [these](/docs/ops/telemetry/in-proxy-service-telemetry/) instructions to try it out.
+- **Removed** time diff info in the proxy-status command.