Bump checkstyle from 6.19 to 8.29 in /code-assert

Bumps [checkstyle](https://github.com/checkstyle/checkstyle) from 6.19 to 8.29.
- [Release notes](https://github.com/checkstyle/checkstyle/releases)
- [Commits](checkstyle/checkstyle@checkstyle-6.19...checkstyle-8.29)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

code-assert/pom.xml

@@ -13,7 +13,7 @@
 
     <properties>
         <module.name>guru.nidi.codeassert</module.name>
-        <checkstyle.version>6.19</checkstyle.version>
+        <checkstyle.version>8.29</checkstyle.version>
         <findbugs.version>3.1.12</findbugs.version>
         <findsecbugs.version>1.9.0</findsecbugs.version>
         <pmd.version>5.8.1</pmd.version>