Kollaborate Server: Critical PHP vulnerability

There is a critical vulnerability in all versions of PHP that can cause remote code excution. This means all versions of Kollaborate Server are vulnerable. You do not need to install a newer version of Kollaborate itself to fix this, just run "docker compose build --no-cache" and "docker compose up -d" again to install the patched version.

We are planning an update to ensure all users get the latest patch, but it is not necessary to install the update to fix the issue.