Merge pull request #20 from Cantara/renovate/major-guava.version

Update dependency com.google.guava:guava to v30

pom.xml

@@ -59,7 +59,7 @@
         <spring.version>5.3.9</spring.version>
         <hibernate-validator.version>5.4.3.Final</hibernate-validator.version>
         <constretto.version>2.2.3</constretto.version>
-        <guava.version>18.0</guava.version>
+        <guava.version>30.1.1-jre</guava.version>
         <assertj.version>3.20.2</assertj.version>
         <junit.version>4.12</junit.version>
         <mockito.version>1.10.19</mockito.version>