fix: generator/schema2template-maven-plugin/pom.xml to reduce vulnera…

…bilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-COMGOOGLEGUAVA-5710356

generator/schema2template-maven-plugin/pom.xml

@@ -34,7 +34,7 @@
     <version>0.12.0-SNAPSHOT</version>
     <packaging>maven-plugin</packaging>
     <properties>
-        <maven.version>3.9.3</maven.version>
+        <maven.version>3.9.4</maven.version>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
     <dependencies>