chore: add action.yml to Issue validator action (#37950)

See: https://github.com/vercel/next.js/runs/7024234103?check_suite_focus=true#step:2:1

## Bug

- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`

## Documentation / Examples

- [ ] Make sure the linting passes by running `pnpm lint`
- [ ] The examples guidelines are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)

.github/actions/issue-validator/action.yml

@@ -0,0 +1,6 @@
+name: Issue validator
+description: 'Validates bug reports on the Next.js repository'
+author: 'Vercel'
+runs:
+  using: 'node18'
+  main: 'index.js'