build(deps): bump org.mockito:mockito-core from 5.20.0 to 5.21.0

Bumps [org.mockito:mockito-core](https://github.com/mockito/mockito) from 5.20.0 to 5.21.0.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](mockito/mockito@v5.20.0...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] <support@github.com>

Author: dependabot[bot]

buttplug4j/build.gradle

@@ -15,7 +15,7 @@ dependencies {
     api 'com.fasterxml.jackson.core:jackson-databind:2.20.1'
     testImplementation 'org.junit.jupiter:junit-jupiter:6.0.1'
     testImplementation 'dev.harrel:json-schema:1.8.2'
-    testImplementation 'org.mockito:mockito-core:5.20.0'
+    testImplementation 'org.mockito:mockito-core:5.21.0'
     testRuntimeOnly 'org.junit.platform:junit-platform-launcher:6.0.1'
     testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:6.0.1'
 }