Bump library/nginx from 1.21.6-alpine to 1.23.0-alpine

Bumps library/nginx from 1.21.6-alpine to 1.23.0-alpine.

---
updated-dependencies:
- dependency-name: library/nginx
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Dockerfile

@@ -159,7 +159,7 @@ RUN chmod +x /usr/local/bin/php-fpm-healthcheck \
 
 EXPOSE 9000
 
-FROM docker.io/library/nginx:1.21.6-alpine as humhub_nginx
+FROM docker.io/library/nginx:1.23.0-alpine as humhub_nginx
 
 LABEL variant="nginx"