Bump github.com/stretchr/testify from 1.8.4 to 1.9.0

Bumps [github.com/stretchr/testify](https://github.com/stretchr/testify) from 1.8.4 to 1.9.0.
- [Release notes](https://github.com/stretchr/testify/releases)
- [Commits](https://github.com/stretchr/testify/compare/v1.8.4...v1.9.0)

---
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>

go.mod

@@ -4,7 +4,7 @@ go 1.20
 
 require (
 	github.com/gorilla/mux v1.8.1
-	github.com/stretchr/testify v1.8.4
+	github.com/stretchr/testify v1.9.0
 	golang.org/x/mod v0.14.0
 	gopkg.in/yaml.v2 v2.4.0
 )