Update 3.9.15.md

Author: michaelklishin

release-notes/3.9.15.md

@@ -73,7 +73,7 @@ Contributors are encouraged to update them together with their changes. This hel
 
 ## Dependency Upgrades
 
- * `ra` upgraded [from `2.0.4` to `2.0.6`](https://github.com/rabbitmq/ra/compare/v2.0.4...v2.0.6)
+ * `ra` upgraded [from `2.0.4` to `2.0.7`](https://github.com/rabbitmq/ra/compare/v2.0.4...v2.0.7)
  * `prometheus` upgraded from [`4.8.1` to `4.8.2`](https://github.com/deadtrickster/prometheus.erl/compare/06425c21a39c1564164f1cc3fe5bdfa8b23b1f78...v4.8.2)