Add package-info.java to integration

Author: acktsap

Diff for: spring-batch-integration/src/main/java/org/springframework/batch/integration/package-info.java

@@ -0,0 +1,7 @@
+/**
+ * Provides integration with Spring Integration.
+ */
+@NonNullApi
+package org.springframework.batch.integration;
+
+import org.springframework.lang.NonNullApi;