oCIS-wopi example fails with permission error

[pascalwengerter]

Describe the bug

Came across this when working on #2418, should be easy to fix

Steps to reproduce

Steps to reproduce the behavior:

1. Follow https://owncloud.dev/ocis/deployment/ocis_wopi/ guide
2. Starting oCIS Docker container fails with Can't modify config/config.json - permission denied
3. Disabling line 5&6 in entrypoint-override.sh and adding the WEB_UI_CONFIG: "/config/config.dist.json" in the docker-compose lets the oCIS Docker container start

Expected behavior

Guide just works

Actual behavior

Modification needed, no custom domains possible

Setup

oCIS 1.11.0-rc1

[pascalwengerter]

Turns out the same is true for the ocis hello as mentioned in the public rocket chat https://talk.owncloud.com/channel/ocis?msg=JXQjAF9YZ5FrgpX9W

[wkloucek]

regression introduced in #2380 since we don't use root anymore and the file is not writeable by the non-root user. Will have a look :-)