Bump alpine from 3.18.2 to 3.18.4 in /.ci/release-ci/alpine

Bumps alpine from 3.18.2 to 3.18.4.

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

Signed-off-by: dependabot[bot] <support@github.com>

.ci/release-ci/alpine/Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine:3.18.2
+FROM alpine:3.18.4
 
 LABEL maintainer="mail@sobolevn.me"
 LABEL vendor="git-secret team"