Fix Maven warning

[WARNING] Parameter 'headerFile' is unknown for plugin
'maven-checkstyle-plugin:3.2.2:check (default-cli)'

Author: garydgregory

pom.xml

@@ -299,7 +299,6 @@ limitations under the License.
           <configuration>
             <configLocation>${checkstyle.config.file}</configLocation>
             <enableRulesSummary>false</enableRulesSummary>
-            <headerFile>${checkstyle.header.file}</headerFile>
             <includeTestSourceDirectory>true</includeTestSourceDirectory>
             <resourceExcludes>NOTICE.txt,LICENSE.txt,**/pom.properties,**/sha512.properties</resourceExcludes>
           </configuration>