[Checkstyle] Fix package name of allowed Apache FileUtils

Author: valfirst

3.0/config/checkstyle/checkstyle.xml

@@ -31,7 +31,7 @@
     <module name="IllegalImport">
       <property name="id" value="bannedFileUtilsOtherThanApacheCommonsLang3" />
       <property name="regexp" value="true" />
-      <property name="illegalClasses" value="^.+(?&lt;!org\.apache\.commons\.lang3\.)FileUtils.*" />
+      <property name="illegalClasses" value="^.+(?&lt;!org\.apache\.commons\.io\.)FileUtils.*" />
     </module>
     <module name="IllegalImport">
       <property name="id" value="bannedJavaEmptyCollections" />