Updated release notes for HttpCore 5.5-beta1 release

Author: arturobernalg

RELEASE_NOTES.txt

@@ -1,3 +1,72 @@
+Release 5.5-beta1
+-----------------
+
+This is the first BETA release in the 5.5 release series.
+
+Compared to 5.5-alpha1, this release improves connection pool behaviour,
+timeout handling in the reactor and HTTP/2 transport, message header
+processing utilities, JSON async entity producer support, and ContentType
+parsing.
+
+Notable changes since 5.5-alpha1:
+* Reduce contention and disposer back-pressure in RouteSegmentedConnPool.
+* Add configurable HTTP/2 PING ACK timeout.
+* Use monotonic time for reactor and HTTP/2 timeout accounting.
+* Fix H2 stream timeout handling on inbound frames.
+* Add strict header and header element parsing methods to MessageSupport.
+* Add header value transformation method to MessageSupport.
+* Add path segment codec APIs.
+* Add content type support to JSON async entity producers.
+* Optimize ContentType parsing.
+* Ensure async data consumers can avoid NPE if they have been canceled or
+  released concurrently with data processing.
+
+Change Log
+-------------------
+* Add deterministic, sleep-free connection pool fuzzer.
+  Contributed by Arturo Bernal <abernal at apache.org>
+
+* Require Java 17+ for Maven runtime.
+  Contributed by Ryan Schmitt <rschmitt at apache.org>
+
+* Ensure async data consumers can avoid NPE if they have been canceled /
+  released from another thread at the same time as concurrent data
+  processing.
+  Contributed by Oleg Kalnichevski <olegk at apache.org>
+
+* Fix H2 stream timeout handling on inbound frames.
+  Contributed by Arturo Bernal <abernal at apache.org>
+
+* Fix flaky Docker compatibility tests caused by EMFILE in httpd container.
+  Contributed by Arturo Bernal <abernal at apache.org>
+
+* MessageSupport: methods for strict header and header element parsing.
+  Contributed by Oleg Kalnichevski <olegk at apache.org>
+
+* Add content type support to JSON async entity producers.
+  Contributed by Arturo Bernal <abernal at apache.org>
+
+* Use monotonic time for reactor and H2 timeout accounting.
+  Contributed by Arturo Bernal <abernal at apache.org>
+
+* Updated JSON binding and async examples.
+  Contributed by Oleg Kalnichevski <olegk at apache.org>
+
+* Configurable HTTP/2 PING ACK timeout.
+  Contributed by Arturo Bernal <abernal at apache.org>
+
+* Path segment codec APIs.
+  Contributed by Oleg Kalnichevski <olegk at apache.org>
+
+* Reduce contention and disposer back-pressure in RouteSegmentedConnPool.
+  Contributed by Arturo Bernal <abernal at apache.org>
+
+* Added header value transformation method to MessageSupport.
+  Contributed by Oleg Kalnichevski <olegk at apache.org>
+
+* Optimization of ContentType parsing.
+  Contributed by Oleg Kalnichevski <olegk at apache.org>
+  
 Release 5.5-alpha1
 ------------------