feat: add docker-compose.prod.override.yml support

[rhysyngsun]

This adds support for an optional docker-compose.prod.override.yml file used for tutor local commands. I'm proposing this because the current documentation suggests you can use docker-compose.override.yml to override services defined in docker-compose.prod.yml, but in practice this always errors.

Any tutor dev commands will try to use it and fail. Additionally even trying to run tutor local start (really anything that invokes docker compose [start|up|restart]) causes the equivalent of tutor dev dc stop to run, which will fail as services like caddy aren't defined for that project.

This example if put in docker-compose.override.yml will fail (under both tutor dev and tutor local), but if put in docker-compose.prod.override.yml both commands will work as expected:

services:
  caddy:
    labels:
      - "key=value"

[DawoudSheraz]

• please add your github username at the end of changelog entry.

[regisb]

Note that adding the username in the changelog entry is optional. If OP does not need public recognition, that's fine :-)

[DawoudSheraz]

@rhysyngsun Hi, are you good with merging this without mentioning your GitHub in the changelog entry? You can update the changelog if you want to. Thanks

[rhysyngsun]

You can merge it as-is.

[DawoudSheraz]

Once the changelog is updated, this will be merged.