Change log:
0d37566 GH-2744: ScatterGather: reinstate request headers
d38db25 Fix updateCopyrights Gradle task
fe5d0af Optimize checkTestConfigs task for UP_TO_DATE
1fad620 Upgrade Spring Data & security; fix docs path
9879c74 Upgrade dependencies, including Kotlin
daf0015 Add updateCopyrights Gradle task
53272fd Remove unused import
e8aa861 GH-2735: Add errorChannel to ScatterGatherHandler
5c46efe Fix Sonar smells for websocket module
5eba369 Fix new Sonar smells in MessagingGatewaySupport
4c88ddd GH-2731: Fix nested gateway error propagation
37563a1 Polish Contribution Guidelines
04875b7 GH-2727: Ensure JDBC queries are logged (#2730)
71fd60f Add default expressions for ExpEvalReqHAdvice (#2738)
e2d177e Fix "One sentence per line" in docs
d56e29b GH-2733: Polishing
f6c8a65 GH-2733: Fix Meter Memory Leak
6391e4b Tcp Doc Polishing
f82c716 GH-2728: AMQP Manual acks and conversion errors
65b8899 Revert INT-4386: Support Instant in schedule expr.
f901c4e INT-4386: Support Instant in schedule expressions
020ea76 Make IOS.setTaskScheduler() as public (#2725)
7980afe INT-4339: Remove Docbook & rely on Asciidoctor
a283ad6 GH-2723: Handle unsupported XML properties
4c6ffec * Fix some typos in Docs, old DSL callbacks
5295a76 Fix mail lock race condition & Sonar smells (#2721)
a609bd9 Some file module Sonar fixes (#2718)
db239f8 Fix NPE Sonar report in the NotificationPublishMH
9ab6779 Fix new Sonar smell and some other in JMX module (#2716)
bac3565 GH-2714: Fix PollSkipAdvice
fff968e Add Duration overloads to Pollers factory
8002275 INT-2549: Ignore MBean call reply in op-invoc-c-a
f43fa97 Update issue template
5b42c28 Refactor AbstractMailReceiver for proper locking
690a2c3 Implement Lifecycle for IntegrationComponentSpec
119db81 * Fix new Sonar issue in the AbstractMailReceiver (#2709)
d37e656 Fix DSL to deal with beanNames for handlers (#2707)
a5e437f INT-2543: Relax mail host when mail-props present
0ac7660 Fix a couple new Sonar smells
7da77f7 INT-1887: Optimize AbstractMailReceiver.receive()
4ea3b1c GH-2705: public CTORs on AMFPFileListFilter Impls
48ae91e Docs: Fix File.renameTo() Expressions
462dc98 GH-2695: Add proxy option to @EnablePublisher (#2701)
cd8cbaa GH-2699: Make expressions cache concurrent
eed16f0 Fix BeanFactory propagation for MMInvokerHelper (#2694)
63684e2 INT-4574: JDBC: Add NOT NULL for primary keys
936d63b Update CONTRIBUTING for GH issues bug tracking (#2696)
518c491 TcpCodecs factory Sonar polishing
4dcbb92 Upgrade spring-retry
ae3bb15 TcpCodecs factory improvement