Bump react/promise-timer from 1.7.0 to 1.8.0

Bumps [react/promise-timer](https://github.com/reactphp/promise-timer) from 1.7.0 to 1.8.0.
- [Release notes](https://github.com/reactphp/promise-timer/releases)
- [Changelog](https://github.com/reactphp/promise-timer/blob/1.x/CHANGELOG.md)
- [Commits](reactphp/promise-timer@v1.7.0...v1.8.0)

---
updated-dependencies:
- dependency-name: react/promise-timer
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]