* Move `What's New` into `changes-5.1-5.2.adoc`
* Remove version from the `XSD` files:
1. Align with SF
2. The version for XSD doesn't matter for the current jar version,
since only the version is available in classpath is from the current
jar version
3. Modify `spring.schemas` to map all the possible versions for XSD
into the current one in a jar.
This way target applications can upgrade without changing the version
for XSD location and we don't need to require `versionless` variant
any more
4. The jar in classpath can handle only its own XSD, so independently
of version or no-version variants we still may fail because the current
jar may not support end-user code any more - need some fix over there
anyway.
* Remove `checkTestConfigs` Gradle task since we don't worry about XSD
version any more
* Modify `schemaZip` Gradle task to populate XSDs into a distribution
still with a version to avoid overriding on-line XSDs for version `1.0.x`.
We may consider not do that since SF doesn't and just bite a bullet
for always overriding those on-line XSDs to the actual one from the latest
release.
Fixes https://github.com/spring-projects/spring-integration/issues/2987
To resolve XSD files properly from the classpath, their HTTPS reference
must be present in the `spring.schemas` to avoid the Internet interaction
for resolving an XSD file
**Cherry-pick to 5.1.x, 5.0.x & 4.3.x**
* Do not fix urls for the `http://apache.org/xml/features` when we
configure XML components
* Do not fix urls for localhost and fake links in tests
* Fix all the dead links in docs
JIRA: https://jira.spring.io/browse/INT-3581
Move schemas to 4.2.
Add `selector-expression` to `<wire-tap/>`.
INT-3781: Fix What's New
Bump Namespace Version to 4.2
JIRA: https://jira.spring.io/browse/INT-3511
Add note about Broker destinations
Doc Polishing
INT-3511: Fix 'useBroker' Docs and provide compatibility with SF 4.1.1
JIRA: https://jira.spring.io/browse/INT-1198
INT-1198: WebSocket: Add namespace support
Polishing components according to the namespace support experience
Parser for `<server-container>` and tests
INT-1198: Add parser tests for `<int-websocket:outbound-channel-adapter>`
Introduce `use-broker` on server side
Polishing according PR comments
`What's New` note
