Update example docker docs to work out of the box

[stankud]

Background

This change attempts to provide a more streamlined user experience by updating the documentation in the docker section to work out of the box

Changes

The "Bind mount a volume" (-v) param value in the example docker command changes the target from /app/auto_gpt_workspace to the actual directory used by autogpt by default, which is /home/appuser/auto_gpt_workspace

Documentation

This change is to the actual documentation

Test Plan

I tested this by starting a docker container with the updated -v param value and insured that the files autogpt wrote to auto_gpt_workspace folder were also persisted on my local machine in auto_gpt_workspace folder.

PR Quality Checklist

• My pull request is atomic and focuses on a single change.
• I have thoroughly tested my changes with multiple different prompts.
• I have considered potential risks and mitigations for my changes.
• I have documented my changes clearly and comprehensively.
• I have not snuck in any "extra" small tweaks changes

No tests need because it's a documentation change.

[Pwuts]

#1843 would also fix it, by changing back the workdir 😅

[stankud]

Ah yes - that's probably a better way to solve this. I'll close.

[stankud]

#1843 fixes this