[#482] upgrade maven-core version to latest to fix guava dependency

pom.xml

@@ -61,7 +61,7 @@
     <!-- used by maven-plugin prerequisites -->
     <maven.minimal.version>3.1.0</maven.minimal.version>
     <!-- maven api properties (overriden in check-maven-prerequisites profile -->
-    <maven.version>3.8.8</maven.version>
+    <maven.version>3.9.6</maven.version>
     <maven-plugin-annotations.version>3.8.2</maven-plugin-annotations.version>
     <maven.plugin.testing.version>3.3.0</maven.plugin.testing.version>