Update CHANGELOG.md for 0.20.6

gstreamer/CHANGELOG.md

@@ -5,6 +5,21 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html),
 specifically the [variant used by Rust](http://doc.crates.io/manifest.html#the-version-field).
 
+## [0.20.6] - 2023-06-06
+### Added
+- Getter for the `gst_rtsp_server::RTSPContext` URI field.
+
+### Fixed
+- `gst_pbutils::DiscovererStreamInfo::stream_id()` can return `NULL`. This is
+  mapped to the empty string for this release to keep backwards compatibility.
+- `gst_pbutils::DiscovererStreamInfo` iterator methods can be called on any
+  subclass directly now without casting.
+- Debug logs use the actual function name against instead of the name of a
+  closure generated by the log macros.
+
+### Changed
+- Minor performance improvements to debug logging.
+
 ## [0.20.5] - 2023-04-22
 ### Added
 - `glib::HasParamSpec` impl for miniobjects to allow using them with the