Fix PR link format for 1.13.0.0 release notes (#345)

Author: qreshi

release-notes/opendistro-for-elasticsearch-alerting.release-notes-1.13.0.0.md

@@ -3,15 +3,15 @@
 Compatible with Elasticsearch 7.10.2
 
 ### Bug Fixes
-* Move user instantiation to doExecute [#343](https://github.com/opendistro-for-elasticsearch/alerting/pull/343)
+* Move user instantiation to doExecute ([#343](https://github.com/opendistro-for-elasticsearch/alerting/pull/343))
 
 ### Infrastructure
-* Rename plugin for more consistent naming convention [#339](https://github.com/opendistro-for-elasticsearch/alerting/pull/339)
-* Change release workflow to use new staging bucket for artifacts [#334](https://github.com/opendistro-for-elasticsearch/alerting/pull/339)
+* Rename plugin for more consistent naming convention ([#339](https://github.com/opendistro-for-elasticsearch/alerting/pull/339))
+* Change release workflow to use new staging bucket for artifacts ([#334](https://github.com/opendistro-for-elasticsearch/alerting/pull/339))
 
 ### Documentation
-* Add RFC for Document-Level Alerting [#327](https://github.com/opendistro-for-elasticsearch/alerting/pull/327)
+* Add RFC for Document-Level Alerting ([#327](https://github.com/opendistro-for-elasticsearch/alerting/pull/327))
 
 ### Maintenance
-* Adds support for Elasticsearch 7.10.2 [#340](https://github.com/opendistro-for-elasticsearch/alerting/pull/340)
-* Update cron-utils to version 9.1.3 [#344](https://github.com/opendistro-for-elasticsearch/alerting/pull/344)
+* Adds support for Elasticsearch 7.10.2 ([#340](https://github.com/opendistro-for-elasticsearch/alerting/pull/340))
+* Update cron-utils to version 9.1.3 ([#344](https://github.com/opendistro-for-elasticsearch/alerting/pull/344))