Use mirror for Tomcat downloads

Closes gh-48038

Author: wilkinsona

spring-boot-system-tests/spring-boot-image-tests/src/systemTest/resources/org/springframework/boot/image/paketo/PaketoBuilderTests-plainWarApp.gradle

@@ -48,5 +48,9 @@ war {
 
 bootBuildImage {
 	archiveFile = war.archiveFile
-	environment = ['BP_JVM_VERSION': java.targetCompatibility.getMajorVersion(), 'BP_TOMCAT_VERSION': '10.*']
+	environment = [
+		'BP_JVM_VERSION': java.targetCompatibility.getMajorVersion(),
+		'BP_TOMCAT_VERSION': '10.*',
+		'BP_DEPENDENCY_MIRROR_DOWNLOADS_APACHE_ORG': 'https://archive.apache.org/dist'
+	]
 }