fix: Always include the default app-config.yaml from the Backstage image in the container command

[rm3l]

Description of the change

As reported in #290, deploying the current Helm Chart might result in a Backstage pod not being able to start due to a config validation error. You can run this command from the main branch to reproduce the issue:

helm install my-backstage ./charts/backstage \
  --set backstage.appConfig.app.baseUrl=https://backstage.mydomain.com \
  --set backstage.appConfig.backend.baseUrl=https://backstage.mydomain.com

To fix this issue (and also prevent future similar issues), I thought it would make sense to include the default app-config.yaml file in the backstage-backend container command, just like it is currently done in the backstage Dockerfile.

Existing or Associated Issue(s)

Fixes #290

Additional Information

Checklist

• Chart version bumped in Chart.yaml according to semver.
• Variables are documented in the values.yaml and added to the README.md. The helm-docs utility can be used to generate the necessary content. Use helm-docs --dry-run to preview the content.
• JSON Schema generated.
• List tests pass for Chart using the Chart Testing tool and the ct lint command.

[rm3l]

/cc @ChrisJBurns Thoughts on this? This is confirmed to fix issues like #290
Thanks.

[ChrisJBurns]

@vinzscam Wondering what your thoughts are on this? I always defer to yourself when it comes to some of the app-config changes 😄

[github-actions]

This PR has been automatically marked as stale because it has not had recent activity from the author. It will be closed if no further activity occurs. If the PR was closed and you want it re-opened, let us know and we'll re-open the PR so that you can continue the contribution!

[rm3l]

not stale.
cc @vinzscam Gentle reminder to please take a look when you get a chance. Thanks.

[vinzscam]

I don't think we can assume that app-config.yaml exists. Also this is a breaking change for those adopters that don't want to always include app-config.yaml.

I think the problem is that the techdocs config isn't marked as optional. Opened backstage/backstage#31866

[rm3l]

I don't think we can assume that app-config.yaml exists. Also this is a breaking change for those adopters that don't want to always include app-config.yaml.

I think the problem is that the techdocs config isn't marked as optional. Opened backstage/backstage#31866

That makes sense. Closing this as not needed then. Thanks for your feedback.