build(deps): bump github.com/stretchr/testify from 1.7.5 to 1.8.0

Bumps [github.com/stretchr/testify](https://github.com/stretchr/testify) from 1.7.5 to 1.8.0.
- [Release notes](https://github.com/stretchr/testify/releases)
- [Commits](stretchr/testify@v1.7.5...v1.8.0)

---
updated-dependencies:
- dependency-name: github.com/stretchr/testify
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>