doc(release): prepare for v2.0.0

Signed-off-by: Raphael Defosseux <raphael.defosseux@openairinterface.org>

CHANGELOG.md

 # RELEASE NOTES: #
 
+## v2.0.0 -- December 2023 ##
+
+* Features
+  - Support YAML configuration file
+    * Yaml validation default value
+* Fixes
+  - Handling boolean values in yaml parsing for policies
+* Tech debt
+  - Moved common models to the shared common submodule
+  - Moved PCF Models to the shared common submodule
+  - Switching to clang-format-12
+  - Published image on Docker-Hub is using now Ubuntu-22 as base image
+    * Ubuntu-18 is no longer supported
+
 ## v1.5.1 -- May 2023 ##
 
 * Add HTTP/2 support

README.md

@@ -10,15 +10,17 @@ At the moment, it contains the following network elements:
 
 * Access and Mobility Management Function (**AMF**)
 * Authentication Server Management Function (**AUSF**)
+* Location Management Function (**LMF**)
+* Network Exposure Function (**NEF**)
+* Network Slicing Selection Function (**NSSF**)
 * Network Repository Function (**NRF**)
+* Network Data Analytics Function (**NWDAF**)
+* Policy Control Function (**PCF**)
 * Session Management Function (**SMF**)
 * Unified Data Management (**UDM**)
 * Unified Data Repository (**UDR**)
-* User Plane Function (**UPF**)
-* Network Slicing Selection Function (**NSSF**)
-* Network Data Analytics Function (**NWDAF**)
 * Unstructured Data Storage Function (**UDSF**)
-* Policy Control Function (**PCF**)
+* User Plane Function (**UPF**)
 
 Each has its own repository: this repository (`oai-cn5g-pcf`) is meant for PCF.