build(deps): bump org.mockito:mockito-core from 5.12.0 to 5.21.0

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 5.12.0 to 5.21.0.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](mockito/mockito@v5.12.0...v5.21.0)

---
updated-dependencies:
- dependency-name: org.mockito:mockito-core
  dependency-version: 5.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

build.gradle.kts

@@ -173,7 +173,7 @@ configure(libs) {
             dependency("org.hamcrest:hamcrest:3.0")
             dependency("org.jboss.resteasy:resteasy-client:7.0.1.Final")
             dependency("org.mock-server:mockserver-netty:5.15.0")
-            dependency("org.mockito:mockito-core:5.12.0")
+            dependency("org.mockito:mockito-core:5.21.0")
             dependency("org.slf4j:slf4j-api:${orgSlf4jVersion}")
             dependency("org.slf4j:slf4j-nop:${orgSlf4jVersion}")
             dependency("org.slf4j:slf4j-simple:${orgSlf4jVersion}")