README instructions to run docs-builder

Context: I was trying to run docs-builder locally by following the [README](https://github.com/elastic/docs-builder#). I have set up the Docker account, but when I run the cmd
`docker run -v "./.git:/app/.git" -v "./docs:/app/docs" -v "./.artifacts:/app/.artifacts" \
ghcr.io/elastic/docs-builder:edge`, I get the following error. What is this access I am missing?

```info ::e.d.t.f.topwatchFilter:: generate :: Finished in '00:00:03.2504914'
error::Program :: System.UnauthorizedAccessException: Access to the path '/app/elastic' is denied.
---> System.IO.IOException: Permission denied
--- End of inner exception stack trace ---
at System.IO.FileSystem.CreateParentsAndDirectory(String, UnixFileMode) + 0x291
at System.IO.FileSystem.CreateDirectory(String, UnixFileMode) + 0xad
at System.IO.Directory.CreateDirectory(String) + 0x32
at Documentation.Builder.Cli.CheckForUpdatesFilter.d__4.MoveNext() + 0x276
--- End of stack trace from previous location ---
at Documentation.Builder.Cli.CheckForUpdatesFilter.d__2.MoveNext() + 0x22f
--- End of stack trace from previous location ---
at Elastic.Documentation.Tooling.Filters.CatchExceptionFilter.d__2.MoveNext() + 0x16a
--- End of stack trace from previous location ---
at Elastic.Documentation.Tooling.Filters.StopwatchFilter.d__2.MoveNext() + 0x177
--- End of stack trace from previous location ---
at ConsoleAppFramework.ConsoleApp.d__37.MoveNext() + 0xf5```