When running the script, I faced the following error but it was
difficult to know the root problem due to lack of error handling.
docker tag" requires exactly 2 arguments.
See 'docker tag --help'.
Usage: docker tag SOURCE_IMAGE[:TAG] TARGET_IMAGE[:TAG]
Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
To investigate such errors easily, this adds an error handling.
This fixes the following failures:
./contrib/offline/README.md:14:1 MD014/commands-show-output Dollar signs used before commands without showing output [Context: "$ ./manage-offline-container-i..."]
./contrib/offline/README.md:20:1 MD014/commands-show-output Dollar signs used before commands without showing output [Context: "$ ./manage-offline-container-i..."]
