Bump db2_community/db2 from 12.1.2.0 to 12.1.3.0 in /tooling/docker

Bumps db2_community/db2 from 12.1.2.0 to 12.1.3.0.

---
updated-dependencies:
- dependency-name: db2_community/db2
  dependency-version: 12.1.3.0
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

tooling/docker/db2.Dockerfile

@@ -1,3 +1,3 @@
 # IBM DB2
 # See https://hub.docker.com/r/ibmcom/db2
-FROM icr.io/db2_community/db2:12.1.2.0
+FROM icr.io/db2_community/db2:12.1.3.0