Use HTTPS to fetch XSD file

Author: garydgregory

src/changes/changes.xml

@@ -35,7 +35,7 @@
 
 <document xmlns="http://maven.apache.org/changes/2.0.0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
-    xsi:schemaLocation="http://maven.apache.org/changes/2.0.0 http://maven.apache.org/xsd/changes-2.0.0.xsd">
+    xsi:schemaLocation="http://maven.apache.org/changes/2.0.0 https://maven.apache.org/xsd/changes-2.0.0.xsd">
   <properties>
     <title>Apache Commons CSV Release Notes</title>
   </properties>