chore: fix broken URLs for CheckStyle DTDs.

[skip ci]

Author: php-coder

src/main/config/checkstyle-suppressions.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" ?>
 <!DOCTYPE suppressions PUBLIC
 	"-//Puppy Crawl//DTD Suppressions 1.0//EN"
-	"http://www.puppycrawl.com/dtds/suppressions_1_0.dtd">
+	"https://checkstyle.org/dtds/suppressions_1_0.dtd">
 
 <suppressions>
 

src/main/config/checkstyle.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <!DOCTYPE module PUBLIC
     "-//Puppy Crawl//DTD Check Configuration 1.2//EN"
-    "http://www.puppycrawl.com/dtds/configuration_1_2.dtd">
+    "https://checkstyle.org/dtds/configuration_1_2.dtd">
 
 <!--