Update Checkstyle DTD version from 1.0 to 1.2
diff --git a/src/conf/checkstyle-suppressions.xml b/src/conf/checkstyle-suppressions.xml
index e0ef08d..0919ab6 100644
--- a/src/conf/checkstyle-suppressions.xml
+++ b/src/conf/checkstyle-suppressions.xml
@@ -1,32 +1,28 @@
 <?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">
-<!-- SEE: http://checkstyle.sourceforge.net/config.html#Examples -->
+    "-//Checkstyle//DTD SuppressionFilter Configuration 1.2//EN"
+    "https://checkstyle.org/dtds/suppressions_1_2.dtd">
 <suppressions>
-    <suppress checks="LineLength"  files="InstructionFinder.java"/> <!-- TODO later -->
-
-    <suppress checks="MagicNumber" files="VerifierAppFrame.java"/> <!-- Swing files use lots of numbers -->
-    <suppress checks="MagicNumber" files="VerifyDialog.java"/> <!-- Swing files use lots of numbers -->
-    <suppress checks="MagicNumber" files="src[/\\]test[/\\]"/> <!-- test files need numbers -->
-
-     <!-- Maven generated code -->
-    <suppress checks=".*"          files="[/\\]target[/\\]"/>
+  <suppress checks="LineLength"  files="InstructionFinder.java"/> <!-- TODO later -->
+  <suppress checks="MagicNumber" files="VerifierAppFrame.java"/> <!-- Swing files use lots of numbers -->
+  <suppress checks="MagicNumber" files="VerifyDialog.java"/> <!-- Swing files use lots of numbers -->
+  <suppress checks="MagicNumber" files="src[/\\]test[/\\]"/> <!-- test files need numbers -->
+   <!-- Maven generated code -->
+  <suppress checks=".*"          files="[/\\]target[/\\]"/>
 </suppressions>