build(deps): bump io.mockk:mockk from 1.13.6 to 1.13.8

Bumps [io.mockk:mockk](https://github.com/mockk/mockk) from 1.13.6 to 1.13.8.
- [Release notes](https://github.com/mockk/mockk/releases)
- [Commits](https://github.com/mockk/mockk/commits/1.13.8)

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

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

library/build.gradle

@@ -63,7 +63,7 @@ dependencies {
     testImplementation 'junit:junit:4.13.2'
     testImplementation 'org.robolectric:robolectric:4.10.3'
     testImplementation 'net.sf.kxml:kxml2:2.3.0'
-    testImplementation "io.mockk:mockk:1.13.6"
+    testImplementation "io.mockk:mockk:1.13.8"
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
 }