Bump checkstyle from 8.18 to 8.29 in /testsuite (strimzi#28)

* Bump checkstyle from 8.18 to 8.29 in /testsuite

Bumps [checkstyle](https://github.com/checkstyle/checkstyle) from 8.18 to 8.29.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](checkstyle/checkstyle@checkstyle-8.18...checkstyle-8.29)

Signed-off-by: dependabot[bot] <support@github.com>

* Bump the Maven checkstyle plugin

Signed-off-by: Jakub Scholz <www@scholzj.com>

Co-authored-by: Jakub Scholz <www@scholzj.com>

Author: dependabot[bot]

testsuite/pom.xml

@@ -34,7 +34,7 @@
         <maven.compiler.version>3.8.1</maven.compiler.version>
         <maven.resources.version>3.1.0</maven.resources.version>
         <maven.dependency.version>3.1.1</maven.dependency.version>
-        <maven.checkstyle.version>3.0.0</maven.checkstyle.version>
+        <maven.checkstyle.version>3.1.0</maven.checkstyle.version>
         <version.arquillian_universe>1.2.0.2</version.arquillian_universe>
         <version.junit>4.12</version.junit>
         <bouncycastle.version>1.60</bouncycastle.version>
@@ -222,7 +222,7 @@
                     <dependency>
                         <groupId>com.puppycrawl.tools</groupId>
                         <artifactId>checkstyle</artifactId>
-                        <version>8.18</version>
+                        <version>8.29</version>
                     </dependency>
                 </dependencies>
                 <executions>