Bump alpine from 3.18.3 to 3.18.4 in /docker/production

Bumps alpine from 3.18.3 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>

docker/production/Dockerfile

@@ -16,7 +16,7 @@ RUN --mount=type=cache,target=/go/pkg/mod/cache \
   go generate ./... \
   && go build -o collection -ldflags "-s -w"
 
-FROM alpine:3.18.3
+FROM alpine:3.18.4
 
 WORKDIR /go/src/github.com/traPtitech/trap-collection-server