Bump org.apache.maven:maven-model from 3.8.7 to 3.9.0 in /examples

Bumps [org.apache.maven:maven-model](https://github.com/apache/maven) from 3.8.7 to 3.9.0.
- [Release notes](https://github.com/apache/maven/releases)
- [Commits](apache/maven@maven-3.8.7...maven-3.9.0)

---
updated-dependencies:
- dependency-name: org.apache.maven:maven-model
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

examples/test-maven-plugin/build.gradle

@@ -5,7 +5,7 @@ plugins {
 
 dependencies {
     api 'org.apache.maven:maven-core:3.8.7'
-    api 'org.apache.maven:maven-model:3.8.7'
+    api 'org.apache.maven:maven-model:3.9.0'
     api 'org.apache.maven:maven-plugin-api:3.9.0'
 
     compileOnly 'org.apache.maven.plugin-tools:maven-plugin-annotations:3.7.1'