Update samples to use Spring Security 6

Issue gh-46

servlet/java-configuration/hello-mvc-security/gradle/gretty.gradle

@@ -1,5 +1,5 @@
 gretty {
-	servletContainer = "tomcat9"
+	servletContainer = "tomcat10"
 	contextPath = "/"
 	fileLogEnabled = false
 	integrationTestTask = 'integrationTest'
@@ -38,4 +38,4 @@ project.tasks.matching { it.name == "integrationTest" }.all {
 		integrationTest.systemProperty 'app.httpBaseURI', httpBaseUrl
 		integrationTest.systemProperty 'app.httpsBaseURI', httpsBaseUrl
 	}
-}
+}