ReleaseNotes: Update release notes for v8.1.6 (#40025)

docs/sources/release-notes/_index.md

@@ -8,6 +8,7 @@ weight = 10000
 Here you can find detailed release notes that list everything that is included in every release as well as notices
 about deprecations, breaking changes as well as changes that relate to plugin development.
 
+- [Release notes for 8.1.6]({{< relref "release-notes-8-1-6" >}})
 - [Release notes for 8.1.5]({{< relref "release-notes-8-1-5" >}})
 - [Release notes for 8.1.4]({{< relref "release-notes-8-1-4" >}})
 - [Release notes for 8.1.3]({{< relref "release-notes-8-1-3" >}})

docs/sources/release-notes/release-notes-8-1-6.md

@@ -0,0 +1,13 @@
++++
+title = "Release notes for Grafana 8.1.6"
+[_build]
+list = false
++++
+
+<!-- Auto generated by update changelog github action -->
+
+# Release notes for Grafana 8.1.6
+
+### Bug fixes
+
+- **Security**: Fixes CVE-2021-39226. For more information, see our [blog](https://grafana.com/blog/2021/10/05/grafana-7.5.11-and-8.1.6-released-with-critical-security-fix/)