v3.0.0-M2

Change log:

65edbde Upgrade Gradle
e4ea880 Upgrade versions; prepare for release
d8aafda Remove usage of obsolete NestedIOException
0ccfcbe GH-1433: Fix DMLC Monitor Thread Name
d5e7c3f Add checkConf&Returns into RoutingCF.addTargetCF
a1aba73 Fix eviction logic in the PooledChannelCF
909ba57 Fix PooledChannelConnectionFactory
cdf1a9c GH-1420: Move 2.4.x What's New to Appendix
1cbdb7d GH-1251: Jackson2JsonMessageConverter Improvements
ad17638 Remove Invalid Deprecation Suppressions
a3aedc6 Revise Issue Template etc.
8b2cc61 GH-1422: @RabbitListener: Fix Broker-Named Queues
49bc52d fix multi-rabbit example
4309ff3 Remove declareCollections from Doc
c27d966 Restore file.encoding