Merge pull request 'chore(deps): update docker base image to v1.31' (#8) from renovate/docker-base-image into main

Dockerfile

@@ -1,7 +1,7 @@
 # Lightweight, non-root nginx serving the static site.
 # Runs as user "nginx" and listens on 8080, ready to sit behind an
 # external reverse proxy that terminates TLS and forwards requests.
-FROM nginxinc/nginx-unprivileged:1.27-alpine-slim
+FROM nginxinc/nginx-unprivileged:1.31-alpine-slim@sha256:6616de6eaa82bc2ee3541fa287a8fca7dc7271e6374e9402014dbd13f4a980ae
 
 COPY default.conf /etc/nginx/conf.d/default.conf
 COPY --chown=nginx:nginx index.html styles.css script.js messages.js /usr/share/nginx/html/