Bump de.thetaphi:forbiddenapis from 3.8 to 3.9 (#255)

Bumps [de.thetaphi:forbiddenapis](https://github.com/policeman-tools/forbidden-apis) from 3.8 to 3.9.
- [Commits](policeman-tools/forbidden-apis@3.8...3.9)

---
updated-dependencies:
- dependency-name: de.thetaphi:forbiddenapis
  dependency-version: '3.9'
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

buildSrc/build.gradle.kts

@@ -11,7 +11,7 @@ dependencies {
     implementation("io.freefair.gradle:lombok-plugin:8.13.1")
     implementation("com.bmuschko:gradle-docker-plugin:9.4.0")
     implementation("gradle.plugin.com.google.gradle:osdetector-gradle-plugin:1.7.3")
-    implementation("de.thetaphi:forbiddenapis:3.8")
+    implementation("de.thetaphi:forbiddenapis:3.9")
     implementation("com.github.spotbugs.snom:spotbugs-gradle-plugin:6.1.7")
     implementation("org.gradle:test-retry-gradle-plugin:1.6.2")
 }