ChangeLog: Release 6.4.0 Stable (#19526)

* ChangeLog: Release 6.4.0 Stable

* Update CHANGELOG.md

* Update CHANGELOG.md

CHANGELOG.md

-# 6.4.0 (unreleased)
+# 6.4.0 (2019-10-01)
+
+### Features / Enhancements
+* **Build**: Upgrade go to 1.12.10. [#19499](https://github.com/grafana/grafana/pull/19499), [@marefr](https://github.com/marefr)
+* **DataLinks**: Suggestions menu improvements. [#19396](https://github.com/grafana/grafana/pull/19396), [@dprokop](https://github.com/dprokop)
+* **Explore**: Take root_url setting into account when redirecting from dashboard to explore. [#19447](https://github.com/grafana/grafana/pull/19447), [@ivanahuckova](https://github.com/ivanahuckova)
+* **Explore**: Update broken link to logql docs. [#19510](https://github.com/grafana/grafana/pull/19510), [@ivanahuckova](https://github.com/ivanahuckova)
+* **Logs**: Adds Logs Panel as a visualization. [#19504](https://github.com/grafana/grafana/pull/19504), [@davkal](https://github.com/davkal)
+
+### Bug Fixes
+* **CLI**: Fix version selection for plugin install. [#19498](https://github.com/grafana/grafana/pull/19498), [@aocenas](https://github.com/aocenas)
+* **Graph**: Fixes minor issue with series override color picker and custom color . [#19516](https://github.com/grafana/grafana/pull/19516), [@torkelo](https://github.com/torkelo)
 
 
 ## Plugins that need updating when upgrading from 6.3 to 6.4
 ## Plugins that need updating when upgrading from 6.3 to 6.4