Update Checkstyle DTD version from 1.0 to 1.2
diff --git a/src/site/resources/checkstyle/checkstyle-suppressions.xml b/src/site/resources/checkstyle/checkstyle-suppressions.xml
index e62645c..fce6b88 100644
--- a/src/site/resources/checkstyle/checkstyle-suppressions.xml
+++ b/src/site/resources/checkstyle/checkstyle-suppressions.xml
@@ -1,27 +1,29 @@
 <?xml version="1.0"?>
 <!--
-Licensed to the Apache Software Foundation (ASF) under one or more
-contributor license agreements.  See the NOTICE file distributed with
-this work for additional information regarding copyright ownership.
-The ASF licenses this file to You under the Apache License, Version 2.0
-(the "License"); you may not use this file except in compliance with
-the License.  You may obtain a copy of the License at
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
 
-     http://www.apache.org/licenses/LICENSE-2.0
+       http://www.apache.org/licenses/LICENSE-2.0
 
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
 -->
-<!DOCTYPE suppressions PUBLIC "-//Checkstyle//DTD SuppressionFilter Configuration 1.0//EN" "https://checkstyle.org/dtds/suppressions_1_0.dtd">
+<!DOCTYPE suppressions PUBLIC
+    "-//Checkstyle//DTD SuppressionFilter Configuration 1.2//EN"
+    "https://checkstyle.org/dtds/suppressions_1_2.dtd">
 <suppressions>
-    <suppress checks="JavadocMethod" files=".*[/\\]test[/\\].*"/>
-    <suppress checks="JavadocPackage" files=".*[/\\]test[/\\].*"/>
-    <!-- exclude generated JMH classes from all checks -->
-    <suppress checks="[a-zA-Z0-9]*" files=".*[/\\]generated-test-sources[/\\].*"/>
-    <suppress checks="RedundantModifier" files="ConstructorUtilsTest" lines="0-99999"/>
-    <!-- Windows-only workaround -->
-    <suppress checks="NewlineAtEndOfFile" files="target[/\\]maven-archiver[/\\]pom.properties"/>
+  <suppress checks="JavadocMethod" files=".*[/\\]test[/\\].*"/>
+  <suppress checks="JavadocPackage" files=".*[/\\]test[/\\].*"/>
+  <!-- exclude generated JMH classes from all checks -->
+  <suppress checks="[a-zA-Z0-9]*" files=".*[/\\]generated-test-sources[/\\].*"/>
+  <suppress checks="RedundantModifier" files="ConstructorUtilsTest" lines="0-99999"/>
+  <!-- Windows-only workaround -->
+  <suppress checks="NewlineAtEndOfFile" files="target[/\\]maven-archiver[/\\]pom.properties"/>
 </suppressions>