Bump dubbo (#782)

Bumps [dubbo](https://github.com/apache/dubbo) from 3.1.3 to 3.1.5.
- [Release notes](https://github.com/apache/dubbo/releases)
- [Changelog](https://github.com/apache/dubbo/blob/3.2/CHANGES.md)
- [Commits](https://github.com/apache/dubbo/compare/dubbo-3.1.3...dubbo-3.1.5)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
diff --git a/99-integration/dubbo-samples-prefer-serialization-test-31x/dubbo-samples-prefer-serialization-test-31x-consumer/pom.xml b/99-integration/dubbo-samples-prefer-serialization-test-31x/dubbo-samples-prefer-serialization-test-31x-consumer/pom.xml
index 8754afd..c7d3ad8 100644
--- a/99-integration/dubbo-samples-prefer-serialization-test-31x/dubbo-samples-prefer-serialization-test-31x-consumer/pom.xml
+++ b/99-integration/dubbo-samples-prefer-serialization-test-31x/dubbo-samples-prefer-serialization-test-31x-consumer/pom.xml
@@ -31,7 +31,7 @@
 
     <properties>
         <!-- Test compatibility with 3.1.x, should not upgrade this version! -->
-        <dubbo_31x.version>3.1.3</dubbo_31x.version>
+        <dubbo_31x.version>3.1.5</dubbo_31x.version>
     </properties>
 
     <dependencies>