## What changes were proposed in this pull request?
Although we use shebang `#!/usr/bin/env bash`, `minikube docker-env` returns invalid commands in `non-bash` environment and causes failures at `eval` because it only recognizes the default shell. We had better add `--shell bash` option explicitly in our `bash` script.
```bash
$ bash -c 'eval $(minikube docker-env)'
bash: line 0: set: -g: invalid option
set: usage: set [-abefhkmnptuvxBCHP] [-o option-name] [--] [arg ...]
bash: line 0: set: -g: invalid option
set: usage: set [-abefhkmnptuvxBCHP] [-o option-name] [--] [arg ...]
bash: line 0: set: -g: invalid option
set: usage: set [-abefhkmnptuvxBCHP] [-o option-name] [--] [arg ...]
bash: line 0: set: -g: invalid option
set: usage: set [-abefhkmnptuvxBCHP] [-o option-name] [--] [arg ...]
$ bash -c 'eval $(minikube docker-env --shell bash)'
```
## How was this patch tested?
Manual. Run the script with non-bash shell environment.
```
bin/docker-image-tool.sh -m -t testing build
```
Closes#24517 from dongjoon-hyun/SPARK-27626.
Authored-by: Dongjoon Hyun <dhyun@apple.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
6c2d351f54