Merge pull request #5 from aiven/dependabot/maven/com.puppycrawl.tools-checkstyle-8.18

Bump checkstyle from 6.19 to 8.18

Author: ivanyu

pom.xml

@@ -70,7 +70,7 @@
 
         <maven-surefire-and-failsafe-plugin.version>2.21.0</maven-surefire-and-failsafe-plugin.version>
 
-        <checkstyle.version>6.19</checkstyle.version>
+        <checkstyle.version>8.18</checkstyle.version>
     </properties>
 
     <dependencies>