Fix Checkstyle suppressions DTD link.
diff --git a/conf/checkstyle-suppressions.xml b/conf/checkstyle-suppressions.xml
index 3b81f36..5954b25 100644
--- a/conf/checkstyle-suppressions.xml
+++ b/conf/checkstyle-suppressions.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 
 <!DOCTYPE suppressions PUBLIC
-    "-//Puppy Crawl//DTD Suppressions 1.0//EN"
+    "-//Checkstyle//DTD SuppressionFilter Configuration 1.0//EN"
     "https://checkstyle.org/dtds/suppressions_1_0.dtd">
 <!--
    Licensed to the Apache Software Foundation (ASF) under one or more