Fix error while running `frontend` in `read_only: true`

When running this:

docker run -d \
    -u 65532 \
    --cap-drop=ALL \
    --read_only true \
    -p 3000:8080 \
    ghcr.io/mathieu-benoit/backstage-frontend:latest

Getting this error:

/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
10-listen-on-ipv6-by-default.sh: info: can not modify /etc/nginx/conf.d/default.conf (read-only file system?)
/docker-entrypoint.sh: Sourcing /docker-entrypoint.d/15-local-resolvers.envsh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
/docker-entrypoint.d/20-envsubst-on-templates.sh: line 53: can't create /etc/nginx/conf.d/default.conf: Read-only file system
20-envsubst-on-templates.sh: Running envsubst on /etc/nginx/templates/default.conf.template to /etc/nginx/conf.d/default.conf

This could be solved by mounting an emptyDir on /etc/nginx/conf.d. All good.

Associated Score file of this:

apiVersion: score.dev/v1b1
metadata:
  name: frontend
containers:
  frontend:
    image: .
    variables:
      APP_CONFIG_app_baseUrl: http://localhost:3000
      APP_CONFIG_backend_baseUrl: http://localhost:7007
    volumes:
      /etc/nginx/conf.d:
        source: ${resources.confd}
        readOnly: false
service:
  ports:
    tcp:
      port: 3000
      targetPort: 8080
resources:
  backend:
    type: service
  confd:
    type: volume

But then still getting this remaining issue at runtime:

/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
10-listen-on-ipv6-by-default.sh: info: Getting the checksum of /etc/nginx/conf.d/default.conf
10-listen-on-ipv6-by-default.sh: info: /etc/nginx/conf.d/default.conf differs from the packaged version
/docker-entrypoint.sh: Sourcing /docker-entrypoint.d/15-local-resolvers.envsh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
20-envsubst-on-templates.sh: Running envsubst on /etc/nginx/templates/default.conf.template to /etc/nginx/conf.d/default.conf
/docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/40-inject-config.sh
Runtime app config: {
  "app": {
    "title": "Hello, Compose!",
    "baseUrl": "http://localhost:3000"
  },
  "backend": {
    "baseUrl": "http://localhost:7007"
  }
}
Writing runtime config to /usr/share/nginx/html/static/module-backstage.40d4822a.js
sed: can't create temp file '/usr/share/nginx/html/static/module-backstage.40d4822a.jsXXXXXX': Read-only file system

Thoughts? Ideas to fix this?

Reproduce the read-only container behavior using the Docker command and associated Score file. Start with /docker-entrypoint.sh and the listed /docker-entrypoint.d/ scripts, then trace the write to /usr/share/nginx/html/static/module-backstage.40d4822a.js. Done means runtime configuration succeeds without writes to the read-only filesystem.