Bump dubbo in /sofa-tracer-plugins/sofa-tracer-dubbo-plugin

Bumps [dubbo](https://github.com/apache/dubbo) from 2.7.3 to 2.7.15.
- [Release notes](https://github.com/apache/dubbo/releases)
- [Changelog](https://github.com/apache/dubbo/blob/3.0/CHANGES.md)
- [Commits](apache/dubbo@dubbo-2.7.3...dubbo-2.7.15)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

sofa-tracer-plugins/sofa-tracer-dubbo-plugin/pom.xml

@@ -15,7 +15,7 @@
         <dependency>
             <groupId>org.apache.dubbo</groupId>
             <artifactId>dubbo</artifactId>
-            <version>2.7.3</version>
+            <version>2.7.15</version>
             <scope>provided</scope>
         </dependency>
         <dependency>