Update checkstyle to 8.10

- fix issues detected
  - YANG custom registrator should be subject to checkstyle
  - fix Java 8 syntax related violations

Change-Id: I0fc52c6612a40d851fd9bc3bf019621776b1f92a
diff --git a/tools/build/conf/pom.xml b/tools/build/conf/pom.xml
index e52327a..fa09c99 100644
--- a/tools/build/conf/pom.xml
+++ b/tools/build/conf/pom.xml
@@ -38,7 +38,7 @@
         <dependency>
             <groupId>com.puppycrawl.tools</groupId>
             <artifactId>checkstyle</artifactId>
-            <version>6.19</version>
+            <version>8.10</version>
         </dependency>
     </dependencies>