See gh-26601

This commit skips the Bintray-related tasks in our CI pipeline and
instead relies on Maven Central for publishing Spring Framework
artifacts.

This commit also updates the CI pipeline to sign the artifacts directly
with the `artifactory-resource`.

Closes gh-26654

See gh-26638

* pr/26651:
  Polish "Update reference to deprecated CronSequenceGenerator"
  Update reference to deprecated CronSequenceGenerator

Closes gh-26651

See gh-26651

See gh-26651

See gh-26638

Closes gh-26649

Includes removeApplicationListeners(Predicate) method in ApplicationEventMulticaster.

Closes gh-26638

See gh-gh-26434

Closes gh-26642

Upgrade to Hibernate ORM 5.4.29, Jackson 2.12.2, Jetty 9.4.38, Jetty Reactive HttpClient 1.1.6, R2DBC Arabba-SR9, JRuby 9.2.16, SnakeYAML 1.28, Checkstyle 8.41

See gh-26434

See gh-26434

Previously we registered 3 AsyncListener's from the request, from the
response, and from the Servlet adapter.

After this change, only the Servlet adapter registers a listener and
the others are delegated to. This consolidates the handling of
AsyncListener events so that it's easier to discover, trace, and
enforce the order of handling.

See gh-26434

Closes gh-26635

This commit makes sure that we let Jackson deal with all the encodings
that it supports, including UTF-16 and UTF-32.

Closes gh-26627

See gh-26619

Prior to this commit, a method-level @CrossOrigin maxAge value did not
override a class-level @CrossOrigin maxAge value. This contradicts the
Javadoc for @CrossOrgin which states the following.

    For those attributes where only a single value can be accepted such
    as allowCredentials and maxAge, the local overrides the global
    value.

This commit ensures that a method-level @CrossOrigin maxAge value
overrides a class-level @CrossOrigin maxAge value.

Closes gh-26619

Prior to this commit, `ServerHttpRequest.mutate()` would not reflect
changes made on the "Accept" and "Content-Type" HTTP headers.
This was due to the fact that the instantiation of a new request based
on the mutated values would not use the writable HTTP headers used
during the mutation, but rather a read-only view of the headers backed
by `ReadOnlyHttpHeaders`.

`ReadOnlyHttpHeaders` caches those values for performance reasons, so
getting those from the new request would not reflect the changes made
during the mutation phase.

This commit ensures that the new request uses the mutated headers.

Fixes gh-26615

Closes gh-26622

This commit makes sure that quoted boundary parameters are supported in
the DefaultPartHttpMessageReader.

Closes gh-26616

See gh-26613