1 6 10 release notes (#8187)

* add release notes for 1.6.10

* fix lint error

* fix lint

* ads CronJob into spelling

* address review comments

* fix lint

* address review comments

* Update content/en/news/releases/1.6.x/announcing-1.6.10/index.md

Co-authored-by: jacob-delgado <jacob.delgado@aspenmesh.io>

* Code review comments

Co-authored-by: “irisdingbj” <irisdingbj@gmail.com>

content/en/news/releases/1.6.x/announcing-1.6.10/index.md

@@ -0,0 +1,24 @@
+---
+title: Announcing Istio 1.6.10
+linktitle: 1.6.10
+subtitle: Patch Release
+description: Istio 1.6.10 patch release.
+publishdate: 2020-09-22
+release: 1.6.10
+aliases:
+    - /news/announcing-1.6.10
+---
+
+This release contains bug fixes to improve robustness. This release note describes
+what’s different between Istio 1.6.9 and Istio 1.6.10.
+
+{{< relnote >}}
+
+## Changes
+
+- **Added** quotes in log sampling config and Stackdriver test
+- **Fixed** gateways missing endpoint instances of headless services ([Istio #27041](https://github.com/istio/istio/issues/27041))
+- **Fixed** locality load balancer settings were applied to inbound clusters unnecessarily ([Istio #27293](https://github.com/istio/istio/issues/27293))
+- **Fixed** unbounded cardinality of Istio metrics for `CronJob` workloads ([Istio #24058](https://github.com/istio/istio/issues/24058))
+- **Improved** envoy to cache readiness value
+- **Removed** deprecated help message for `istioctl manifest migrate` ([Istio #26230](https://github.com/istio/istio/issues/26230))