Bump alpine in /ops/services/container_instances/db_client/image

Bumps alpine from 3.20 to 3.21.

---
updated-dependencies:
- dependency-name: alpine
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

ops/services/container_instances/db_client/image/Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine:3.20
+FROM alpine:3.21
 RUN apk --no-cache add postgresql14-client
 RUN apk add --no-cache bash
 ARG UID=10001