Use HTTPS for external links from XML files where possible

See gh-16314

spring-boot-project/spring-boot-autoconfigure/src/test/resources/META-INF/mappings/non-annotated.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" ?>
 <entity-mappings xmlns="http://xmlns.jcp.org/xml/ns/persistence/orm"
 				 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-				 xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence/orm http://xmlns.jcp.org/xml/ns/persistence/orm_2_1.xsd"
+				 xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence/orm https://www.oracle.com/webfolder/technetwork/jsc/xml/ns/persistence/orm_2_1.xsd"
 				 version="2.1">
 	<entity class="org.springframework.boot.autoconfigure.orm.jpa.mapping.NonAnnotatedEntity">
 		<table name="NON_ANNOTATED"/>

src/checkstyle/checkstyle.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0"?>
-<!DOCTYPE module PUBLIC "-//Puppy Crawl//DTD Check Configuration 1.2//EN" "http://www.puppycrawl.com/dtds/configuration_1_2.dtd">
+<!DOCTYPE module PUBLIC "-//Puppy Crawl//DTD Check Configuration 1.2//EN" "https://checkstyle.org/dtds/configuration_1_2.dtd">
 <module name="com.puppycrawl.tools.checkstyle.Checker">
 	<module name="io.spring.javaformat.checkstyle.SpringChecks" />
 	<module name="com.puppycrawl.tools.checkstyle.TreeWalker">

src/checkstyle/import-control.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0"?>
-<!DOCTYPE import-control PUBLIC "-//Puppy Crawl//DTD Import Control 1.1//EN" "http://www.puppycrawl.com/dtds/import_control_1_1.dtd">
+<!DOCTYPE import-control PUBLIC "-//Puppy Crawl//DTD Import Control 1.1//EN" "https://checkstyle.org/dtds/import_control_1_1.dtd">
 <import-control pkg="org.springframework.boot">
 	<allow pkg=".*" regex="true" />