fix(config): ignore entry options

[codymikol]

This PR contains a:

• [x] bugfix
• [ ] new feature
• [ ] code refactor
• [ ] test update
• [ ] typo fix
• [ ] metadata update

Motivation / Use-Case

karma-webpack will no longer crash when an entry option is set in webpack config, instead a warning will be thrown and the property will be ignored for the time being.

Fixes N/A

Breaking Changes

N/A

Additional Info

N/A