Fixes https://github.com/spring-projects/spring-integration/issues/3428
The Kotlin Gradle plugin starting with Kotlin `1.4` adds a standard
Kotlin lib into `compile` scope fully ignoring an `optional` variant.
See more info here: https://kotlinlang.org/docs/reference/using-gradle.html#dependency-on-the-standard-library
* Add `kotlin.stdlib.default.dependency=false` into `gradle.properties`
to rely only on the explicit dependency definitions in the project config
* Remove explicit Kotlin deps from test scope in the target modules since
it is declared globally for all the modules
* Fix author emails in the `publish-maven.gradle` to their VMware variants
* Remove usage of `org.jetbrains.annotations` in favor of `@Nullable`
from Spring Framework
* Add `org.gradle.caching=true` and `org.gradle.parallel=true` into a `gradle.properties`
* Fix `Matcher` tests in the `spring-integration-test-support` for the latest JUnit 4
* 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.
