meta: use form schema for bug report template

Based on the documentation at https://docs.github.com/en/communities/using-templates-to-encourage-useful-issues-and-pull-requests/syntax-for-issue-forms

You can see it rendered in my fork: https://github.com/targos/node/issues/new?template=1-bug-report.yml Example issue created by submitting this form: https://github.com/targos/node/issues/5