Bump dubbo from 2.7.13 to 2.7.15

Bumps [dubbo](https://github.com/apache/dubbo) from 2.7.13 to 2.7.15.
- [Release notes](https://github.com/apache/dubbo/releases)
- [Changelog](https://github.com/apache/dubbo/blob/3.0/CHANGES.md)
- [Commits](https://github.com/apache/dubbo/compare/dubbo-2.7.13...dubbo-2.7.15)

---
updated-dependencies:
- dependency-name: org.apache.dubbo:dubbo
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

pom.xml

@@ -86,7 +86,7 @@
         <spring.cloud.version>Hoxton.SR12</spring.cloud.version>
 
         <!-- Apache Dubbo -->
-        <dubbo.version>2.7.13</dubbo.version>
+        <dubbo.version>2.7.15</dubbo.version>
         <curator.version>4.0.1</curator.version>
 
         <!-- Apache RocketMQ -->