Ensure checkstyle header file is referenced from parent POM (#1087)

Signed-off-by: Artur Ciocanu <[email protected]>
Co-authored-by: Artur Ciocanu <[email protected]>

Author: artur-ciocanu

checkstyle.xml

@@ -53,7 +53,6 @@
 
     <module name="RegexpHeader">
         <property name="fileExtensions" value="java"/>
-        <property name="headerFile" value=".java_header"/>
     </module>
 
     <module name="TreeWalker">

pom.xml

@@ -210,6 +210,7 @@
         <version>3.4.0</version>
         <configuration>
           <configLocation>checkstyle.xml</configLocation>
+          <headerLocation>.java_header</headerLocation>
           <consoleOutput>true</consoleOutput>
           <violationSeverity>warning</violationSeverity>
           <failOnViolation>true</failOnViolation>