Check entrypoint array for emptiness

[picsel2]

Description

The entrypoint array of BuildahConfigSettings might be empty. It makes no sense to push the --entrypoint argument then, thus breaking the convertArrayToStringArg method.

Related Issue(s)

Closes #136

Checklist

• [ ] This PR includes a documentation change

• [x] This PR does not need a documentation change

• [ ] This PR includes test changes

• [ ] This PR's changes are already tested

• [x] This change is not user-facing
• [x] This change is a patch change
• [ ] This change is a minor change
• [ ] This change is a major (breaking) change

Changes made

This adds a check guard against an empty settings.entrypoint array when constructing the buildah config command line.

[dannywebster]

@divyansh42 Would you mind taking a look at this PR, please? 🙏🏻