build: bump com.vonage:server-sdk from 8.15.0 to 8.15.1

Bumps [com.vonage:server-sdk](https://github.com/Vonage/vonage-java-sdk) from 8.15.0 to 8.15.1.
- [Release notes](https://github.com/Vonage/vonage-java-sdk/releases)
- [Changelog](https://github.com/Vonage/vonage-java-sdk/blob/main/CHANGELOG.md)
- [Commits](Vonage/vonage-java-sdk@v8.15.0...v8.15.1)

---
updated-dependencies:
- dependency-name: com.vonage:server-sdk
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

pom.xml

@@ -55,7 +55,7 @@
     <dependency>
       <groupId>com.vonage</groupId>
       <artifactId>server-sdk</artifactId>
-      <version>8.15.0</version>
+      <version>8.15.1</version>
     </dependency>
     <dependency>
       <groupId>org.jetbrains.kotlin</groupId>