Fix deprecation warnings

* Use `MatcherAssert.assertThat()`
instead of deprecated `Assert.assertThat()`
* Use `IntegrationFlows.fromSupplier(Supplier)`
instead of removed `IntegrationFlows.from(Supplier)`
* Use `org.springframework.integration:spring-integration-test`
throughout the project for more testing utilities

applications/cafe-scripted/src/test/java/org/springframework/integration/samples/cafe/ScriptTests.java

@@ -30,6 +30,7 @@ import org.springframework.scripting.support.ResourceScriptSource;
  *
  */
 public class ScriptTests {
+
 	@Test
 	public void testRuby() {
 		ScriptExecutor executor = ScriptExecutorFactory.getScriptExecutor("ruby");