build: bump alpine from 3.17.3 to 3.18.3

Bumps alpine from 3.17.3 to 3.18.3.

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

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

Author: dependabot[bot]

Dockerfile

@@ -1,6 +1,6 @@
 FROM nginxproxy/docker-gen:0.10.6 AS docker-gen
 
-FROM alpine:3.17.3
+FROM alpine:3.18.3
 
 ARG GIT_DESCRIBE
 ARG ACMESH_VERSION=2.9.0