(fix) Add Dockerfile git safe directory for/app

[pauby]

Description Of Changes

The docker container doesn't without marking the /app directory as safe.

Motivation and Context

Added the git safe directory command to mark /app as safe. Similar change went into blog.

Testing

• I have previewed these changes using the Docker Container or another method before submitting this pull request.

Change Types Made

• Minor documentation fix (typos etc.).
• Major documentation change (refactoring, reformatting or adding documentation to existing page).
• New documentation page added.
• The change I have made should have a video added, and I have raised an issue for this.
  • Issue #

Change Checklist

• Requires a change to menu structure (top or left-hand side)/
• Menu structure has been updated

Related Issue

N/A

[st3phhays]

This LGTM, thanks for getting this fix in!