Bump alpine from 3.18 to 3.19 in /docker/userspacecni

Bumps alpine from 3.18 to 3.19.

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

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

Author: dependabot[bot]

Diff for: docker/userspacecni/Dockerfile

@@ -14,7 +14,7 @@ RUN go mod download \
     && make generate-bin
 #End of builder container
 # Copy build userspace cni bin to a small deployer container
-FROM alpine:3.18@sha256:eece025e432126ce23f223450a0326fbebde39cdf496a85d8c016293fc851978
+FROM alpine:3.19@sha256:51b67269f354137895d43f3b3d810bfacd3945438e94dc5ac55fdac340352f48
 RUN mkdir -p /root/userspace-cni-network-plugin/userspace
 COPY --from=builder /root/userspace-cni-network-plugin/userspace/userspace /root/userspace-cni-network-plugin/userspace/userspace
 CMD ["cp", "-rf", "/root/userspace-cni-network-plugin/userspace/userspace", "/opt/cni/bin"]