deps(docker): bump couchbase in /docker/couchbase-tools (#2788)

Bumps couchbase from enterprise-7.2.4 to enterprise-7.6.0.

---
updated-dependencies:
- dependency-name: couchbase
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

docker/couchbase-tools/Dockerfile

@@ -1,4 +1,4 @@
-FROM couchbase:enterprise-7.2.4
+FROM couchbase:enterprise-7.6.0
 
 MAINTAINER "Tom Manville <tom@kasten.io>"