fix: pom.xml to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-COMGOOGLEGUAVA-1015415

Author: snyk-bot

pom.xml

@@ -72,7 +72,7 @@
         <sonar.organization>jimbethancourt-github</sonar.organization>
         <sonar.host.url>https://sonarcloud.io</sonar.host.url>
 
-        <maven.core.version>3.8.2</maven.core.version>
+        <maven.core.version>3.9.2</maven.core.version>
     </properties>
 
     <modules>