Ignore vendor directory with RuboCop

[mathroule]

Description

Ignore vendor directory with RuboCop.

Related Issues

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (non-breaking change that does not add functionality but updates documentation)
• Chore (non-breaking change that does not add functionality or fix an issue)

Checklist:

• I have read the CONTRIBUTING document.
• Wrote good commit messages
• Feature branch is up-to-date with main, if not - rebase it
• Added tests for all new/changed functionality, including tests for positive and negative scenarios
• The PR relates to only one subject with a clear title and description in grammatically correct, complete sentences