feat!: Add a ruleset powered by unicorn plugin into essentials config

[wakamsha]

What changed / motivation ?

Add a ruleset powered by eslint-plugin-unicorn into essentials config.

It plugin provides over 100 rules that extend the rule concepts provided by ESLint core.

It is expected that introducing it will encourage proper use of naming conventions for variables and functions, regular expressions, and so on.

Linked PR / Issues

• Tracking: ESLint v9 support #269
• Add a ruleset powered by unicorn plugin into essentials config #309
• https://github.com/moneyforward/frontend-forward/issues/174

Type of change

• 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 not work as expected)
• This change requires a documentation update
• Chore (routine task, maintenance, or non-functional change that doesn't modify src or test files)

Pre-flight checklist

• I have read the Contributing Guidelines
• Performed a self-review of my code

References

[taigakiyokawa]

LGTM 🙆‍♂️ Thank you! I read the recommended rules overview and rules that are disabled for our config and why. I didn’t catch the details of all the rules that we will add, but roughly makes sense. Let's move on.