Bump com.couchbase.client:java-client in /modules/couchbase

Bumps [com.couchbase.client:java-client](https://github.com/couchbase/couchbase-jvm-clients) from 3.9.0 to 3.9.1.
- [Commits](couchbase/couchbase-jvm-clients@3.9.0...3.9.1)

---
updated-dependencies:
- dependency-name: com.couchbase.client:java-client
  dependency-version: 3.9.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

modules/couchbase/build.gradle

@@ -5,7 +5,7 @@ dependencies {
     // TODO use JDK's HTTP client and/or Apache HttpClient5
     shaded 'com.squareup.okhttp3:okhttp:5.1.0'
 
-    testImplementation 'com.couchbase.client:java-client:3.9.0'
+    testImplementation 'com.couchbase.client:java-client:3.9.1'
     testImplementation 'org.awaitility:awaitility:4.3.0'
 }