This patch switches the shellcheck image to use the official image
from Docker Hub.
Note that this does not yet update shellcheck to the latest version (v0.5.x);
Shellcheck v0.4.7 added some new checks, which makes CI currently fail, so will
be done in a follow-up PR. Instead, the v0.4.6 version is used in this PR, which
is closest to the same version as was installed in the image before this change;
```
docker run --rm docker-cli-shell-validate shellcheck --version
ShellCheck - shell script analysis tool
version: 0.4.4
license: GNU General Public License, version 3
website: http://www.shellcheck.net
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 388646eab0)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Upstream-commit: b59752479b
Component: cli
The warning can be disabled by setting the environment variable
Signed-off-by: Daniel Nephin <dnephin@docker.com>
Upstream-commit: 12a7387c8e
Component: cli
