2.1.6.RELEASE

Change log:

7705793 GH-994: Improve test
bf097ca Revert AssertJ in CachingConnectionFactoryTests
18b61fd Fix RejectedExecutionException during close
48d5e90 Configurable Key/Trust Store Algorithm
c71ed1e GH-973: Higher order for RabbitListTestBootstrap (#976)
1333fda GH-973: Higher order for RabbitListenerTestHarness
9359d84 Fix generated docs location
85ddd28 GH-967: Use ChannelProxy CL instead of context (#968)