This commit also removes the testRuntime dependency on Hamcrest which
was a workaround for https://github.com/junit-team/junit5/issues/2004.

Closes gh-23604

Since it does not appear that JUnit 4.13 will be released before Spring
Framework 5.2 GA, I am reverting back to JUnit 4.12 for the time being.

See gh-22894

See gh-23604

This commit adds opt-in build scan integration with Gradle Enterprise.
When the GRADLE_ENTERPRISE_URL environment variable is set on a
developer's machine or on CI, a build scan will be automatically
uploaded to Gradle Enterprise at the end of the build.

This initial integration will establish a baseline for Spring
Framework builds. Once that baseline has been established we can use
the build scans to identify ways in which the build can be optimized
and updated to make use of Gradle's build caching which should reduce
build times, significantly so for changes that only affect tasks near
the leaf nodes of the task graph.

See also: 69214429 and eec183ef

The upgrade to 4.x was breaking some behavior in our tests.
We need to reconsider this upgrade and check our mockrestserver usage in
our tests.

This commit reverts all artifactory configuration changes in this
branch. A new build plan has been created for the master branch which is
tailored for the latest Gradle changes made on that branch.

Closes: gh-23579

Prior to this commit, tests in spring-web and spring-webflux were no
longer executed due to the removal of the Hamcrest dependency in
commit bb03cdf5.

... but continue to execute `Abstract*Tests` classes.

As an added bonus, AbstractViewTests is now executed in the build.

Hamcrest is now only used within spring-test for MockMvc support.

Prior to this commit, the Spring Framework build would partially use the
dependency management plugin to import and enforce BOMs.

This commit applies the dependency management plugin to all Java
projects and regroups all version management declaration in the root
`build.gradle` file (versions and exclusions).

Some versions are overridden in specific modules for
backwards-compatibility reasons or extended support.

This commit also adds the Gradle versions plugin that checks for
dependency upgrades in artifact repositories and produces a report; you
can use the following:

    ./gradlew dependencyUpdates

Closes gh-23566

Closes gh-23543

This reverts commit e5b95716.

See gh-23124

This commit makes sure the content of the local maven repository has no
impact on the build

See gh-23124

This commit makes sure we narrow down dependencies of the Spring
Framework to only Maven central. Optional dependencies that are not
available on Maven Central are now served from a more specific
repository (`ext-release-local`).

Closes gh-23124

Closes gh-23536

Closes gh-23535

Since gh-23282, our CI does not apply automatically the Artifactory
Gradle plugin during our build and we're now applying it "manually".
This commit backports this change since the build configuration is
shared between branches.

See gh-23282

take advantage of the symmetrical SocketAcceptor methods now available
on RSocketFactory for both client and server side.