fix: change running user to 1001

This change is needed because of the following error when using the container in Github actions:

```
Traceback (most recent call last):
  File "/usr/local/bin/flux-local", line 33, in <module>
    sys.exit(load_entry_point('flux-local', 'console_scripts', 'flux-local')())
  File "/app/flux_local/tool/flux_local.py", line 61, in main
    asyncio.run(action.run(**vars(args)))
  File "/usr/local/lib/python3.10/asyncio/runners.py", line 44, in run
    return loop.run_until_complete(main)
  File "/usr/local/lib/python3.10/asyncio/base_events.py", line 649, in run_until_complete
    return future.result()
  File "/app/flux_local/tool/diff.py", line 278, in run
    await git_repo.build_manifest(
  File "/app/flux_local/git_repo.py", line 628, in build_manifest
    results = await kustomization_traversal(selector.path, builder)
  File "/app/flux_local/git_repo.py", line 471, in kustomization_traversal
    for result in await asyncio.gather(*tasks):
  File "/app/flux_local/git_repo.py", line 408, in visit_kustomization
    cmd = kustomize.grep(f"kind={CLUSTER_KUSTOMIZE_KIND}", selector.root / path)
  File "/app/flux_local/git_repo.py", line 179, in root
    return repo_root(self.repo)
  File "/app/flux_local/git_repo.py", line 142, in repo_root
    return Path(repo.git.rev_parse("--show-toplevel"))
  File "/usr/local/lib/python3.10/site-packages/git/cmd.py", line 736, in <lambda>
    return lambda *args, **kwargs: self._call_process(name, *args, **kwargs)
  File "/usr/local/lib/python3.10/site-packages/git/cmd.py", line 1316, in _call_process
    return self.execute(call, **exec_kwargs)
  File "/usr/local/lib/python3.10/site-packages/git/cmd.py", line 1111, in execute
    raise GitCommandError(redacted_command, status, stderr_value, stdout_value)
git.exc.GitCommandError: Cmd('git') failed due to: exit code(128)
  cmdline: git rev-parse --show-toplevel
  stderr: 'fatal: detected dubious ownership in repository at '/github/workspace/pr'
To add an exception for this directory, call:

	git config --global --add safe.directory /github/workspace/pr'
```

Dockerfile

@@ -17,4 +17,5 @@ COPY --from=docker.io/bitnami/kubectl:1.28.5            /opt/bitnami/kubectl/bin
 COPY --from=registry.k8s.io/kustomize/kustomize:v5.3.0  /app/kustomize                   /usr/local/bin/kustomize
 COPY --from=ghcr.io/kyverno/kyverno-cli:v1.10.7         /ko-app/kubectl-kyverno          /usr/local/bin/kyverno
 
+USER 1001
 ENTRYPOINT ["/usr/local/bin/flux-local"]