Use HTTPS to fetch XSD files

Author: garydgregory

pom.xml

@@ -15,7 +15,7 @@
    See the License for the specific language governing permissions and
    limitations under the License.
 -->
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/maven-v4_0_0.xsd">
   <parent>
     <groupId>org.apache.commons</groupId>
     <artifactId>commons-parent</artifactId>