build(deps): Bump nginxinc/nginx-unprivileged from 1.27-alpine to 1.31-alpine in /docker - #2

DL4006 warning: Set the SHELL option -o pipefail before RUN with a pipe in it. If you are using /bin/sh in an alpine image or if your shell is symlinked to busybox then consider explicitly setting your SHELL to /bin/ash, or disable this check

DL3022 warning: `COPY --from` should reference a previously defined `FROM` alias