chore: Create a Pull Request Template

[wakamsha]

What changed / motivation ?

Pull request templates allow you to standardize what contributors include when opening pull requests in your repository.

This template is created based on embeddedartistry/templates/oss_docs/PULL_REQUEST_TEMPLATE.md, but in a more simplified form.

Linked PR / Issues

https://github.com/moneyforward/frontend-forward/issues/167

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 Contribution Guidelines
• Performed a self-review of my code

References

• templates/oss_docs/PULL_REQUEST_TEMPLATE.md at master · embeddedartistry/templates

[taigakiyokawa]

I just left a nits comment. You don't have to re-request review to me.