docs(deployment): Update user ownership in docker deployment docs

[alexknipfer]

After testing the new docker deployment documentation, ran into the following error when running the container if you're using next/image:

[Error: EACCES: permission denied, unlink '/app/.next/cache/images/2+fKe4RlpMaSTNc8npKwiCItZgik9aOX9qkxnVSrsUo=/1613616499089.3hEMhfux5+SolMDEVHEaVPK2O0OlcLoYNao0yKpmYeg=.webp'] {
  errno: -13,
  code: 'EACCES',
  syscall: 'unlink',
  path: '/app/.next/cache/images/2+fKe4RlpMaSTNc8npKwiCItZgik9aOX9qkxnVSrsUo=/1613616499089.3hEMhfux5+SolMDEVHEaVPK2O0OlcLoYNao0yKpmYeg=.webp'
}

This change gives the user correct ownership to have the correct permissions.

[alexknipfer]

Should we give ownership to the entire /app directory?

[leerob]

@armand1m @yordis I'd love your opinion here!

[armand1m]

I think that sounds reasonable

[alexknipfer]

Thanks @leerob @armand1m looks like it was merged, but if we want to make that change then we need to change it to RUN chown -R nextjs:nodejs /app

[yordis]

@leerob somehow I failed to see this notification

# Or use the numbers, I don't remember
COPY --chown=nextjs:nodejs --from=builder /app/public ./public

I think you meant to do that instead of moving the statement after the copy but it seems to be the same