changelog: add notes about closing #12747

[skip ci]

CHANGELOG.md

@@ -24,6 +24,7 @@
 * **Cloudwatch**: Improved error handling [#12489](https://github.com/grafana/grafana/issues/12489), thx [@mtanda](https://github.com/mtanda)
 * **Table**: Adjust header contrast for the light theme [#12668](https://github.com/grafana/grafana/issues/12668)
 * **Elasticsearch**: For alerting/backend, support having index name to the right of pattern in index pattern [#12731](https://github.com/grafana/grafana/issues/12731)
+* **Auth**: Fix overriding tls_skip_verify_insecure using environment variable [#12747](https://github.com/grafana/grafana/issues/12747), thx [@jangaraj](https://github.com/jangaraj)
 
 # 5.2.2 (2018-07-25)