v2.1.8.RELEASE

Change log:

19c51ec Upgrade Spring Framework and others
6087886 GH-1058: Fix Reject/Requeue for Async Returns
47e5e17 Fix a ListenerExecutionFailedException usage
c9fd46f Fix ImmediateRequeueAmqpException
586fa83 Fix AssertJ conflicts in new Appender tests
98cb7a1 GH-1049: Support SaslConfig in logging appenders
9c303d2 Add HTTPS entries for XSD into spring.schemas
c5c6ca3 Sleep for failed declaration out of warn block
514fa92 GH-1034: DMLC: Detect target channel changed
6423921 GH-1034: DMLC: Cancel consumer after failed ack
0ff8a81 GH-1038: RT: Fix evaluatedFastReplyTo
715d43d Fix SmartLifecycle.stop(Runnable) usage
f1541f4 GH-1029: Add option to randomize connection order
a567fbb GH-1026: Fix Delay with CacheMode.CONNECTION