Use main Apache archive for Tomcat binaries to improve(?) build stability

Mirrors of archive.apache.org only mirror the latest release of each
project so, as new releases are made, builds using older versions will
break as the mirrors are updated. T

This commit updates the Tomcat deployment test to use the main Apache
archive site. This should provide long-term access to Tomcat binaries,
improving build stability and ensuring that tagged builds are
repeatable.

spring-boot-deployment-tests/spring-boot-deployment-test-tomcat/pom.xml

@@ -19,7 +19,7 @@
 		<main.basedir>${basedir}/../..</main.basedir>
 		<cargo.container.id>tomcat8x</cargo.container.id>
 		<cargo.container.url>
-			http://mirrors.sonic.net/apache/tomcat/tomcat-8/v${tomcat.version}/bin/apache-tomcat-${tomcat.version}.zip
+			http://archive.apache.org/dist/tomcat/tomcat-8/v${tomcat.version}/bin/apache-tomcat-${tomcat.version}.zip
 		</cargo.container.url>
 	</properties>
 	<dependencies>