BUG: buildpacks/base.py: COPY --chmod to allow non-root users to run python3-login and repo2docker-entrypoint

[westurner]

• Fixes Set read and execute (a+rx) permission for the repo2docker-entrypoint file #921 and the /bin/bash: /usr/local/bin/python3-login: Permission denied error
  that's blocking use with repo2podman and rootless containers

[minrk]

Build fails, because this feature is apparently not always supported:

FAILED tests/base/node/verify::build - repo2docker.engine.BuildError: the --chmod option requires BuildKit. Refer to https://docs.docker.com/go/buildkit/ to learn how to build images with BuildKit enabled
FAILED tests/base/node/verify::verify - repo2docker.engine.BuildError: the --chmod option requires BuildKit. Refer to https://docs.docker.com/go/buildkit/ to learn how to build images with BuildKit enabled
FAILED tests/base/node/verify::check-tmp - repo2docker.engine.BuildError: the --chmod option requires BuildKit. Refer to https://docs.docker.com/go/buildkit/ to learn how to build images with BuildKit enabled

[westurner]

Closing as duplicate. See #1395, which has a workaround