Bump ubi9/ubi-micro from 9.4-13 to 9.4-15 in /operator (SeldonIO#5885)

Bumps ubi9/ubi-micro from 9.4-13 to 9.4-15.

---
updated-dependencies:
- dependency-name: ubi9/ubi-micro
  dependency-type: direct:production
...

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

Author: dependabot[bot]

operator/Dockerfile

@@ -18,7 +18,7 @@ COPY operator/main.go main.go
 # Build
 RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -a -o manager main.go
 
-FROM registry.access.redhat.com/ubi9/ubi-micro:9.4-13
+FROM registry.access.redhat.com/ubi9/ubi-micro:9.4-15
 WORKDIR /
 COPY --from=builder /workspace/manager .
 USER 65532:65532