Bump io.mockk:mockk from 1.12.4 to 1.13.8 (#9)

Bumps [io.mockk:mockk](https://github.com/mockk/mockk) from 1.12.4 to 1.13.8.
- [Release notes](https://github.com/mockk/mockk/releases)
- [Commits](mockk/mockk@1.12.4...1.13.8)

---
updated-dependencies:
- dependency-name: io.mockk:mockk
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

build.gradle.kts

@@ -17,7 +17,7 @@ dependencies {
   implementation("io.ktor:ktor-client-cio:1.6.7")
 
   testImplementation("org.junit.jupiter:junit-jupiter:5.8.2")
-  testImplementation("io.mockk:mockk:1.12.4")
+  testImplementation("io.mockk:mockk:1.13.8")
   testImplementation("org.assertj:assertj-core:3.22.0")
   testImplementation("org.mock-server:mockserver-client-java-no-dependencies:5.15.0")
   testImplementation("org.mock-server:mockserver-junit-jupiter-no-dependencies:5.15.0")