Bump maven-hpi-plugin from 3.8 to 3.9

Bumps [maven-hpi-plugin](https://github.com/jenkinsci/maven-hpi-plugin) from 3.8 to 3.9.
- [Release notes](https://github.com/jenkinsci/maven-hpi-plugin/releases)
- [Commits](jenkinsci/maven-hpi-plugin@maven-hpi-plugin-3.8...maven-hpi-plugin-3.9)

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

pom.xml

@@ -54,7 +54,7 @@
     <jenkins-core.version>${jenkins.version}</jenkins-core.version>
     <jenkins-war.version>${jenkins.version}</jenkins-war.version>
     <jenkins-test-harness.version>2.55</jenkins-test-harness.version>
-    <hpi-plugin.version>3.8</hpi-plugin.version>
+    <hpi-plugin.version>3.9</hpi-plugin.version>
     <stapler-plugin.version>1.17</stapler-plugin.version>
     <java.level>you-must-override-the-java.level-property</java.level>
     <plugin.minimumJavaVersion>1.${java.level}</plugin.minimumJavaVersion>