Update CHANGELOG and README with dependency on json-c

Signed-off-by: Anthony PERARD <anthony.perard@vates.tech>
Acked-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

CHANGELOG.md

@@ -14,6 +14,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
  - Debian Trixie added to CI.  Debian Bullseye retired from CI for RISC-V due
    to the baseline change.
  - Linux based device model stubdomains are now fully supported.
+ - New dependency on library json-c, the toolstack will prefer it to `YAJL`
+   when available.
 
  - On x86:
    - Restrict the cache flushing done as a result of guest physical memory map

README

@@ -53,7 +53,7 @@ provided by your OS distributor:
     * Development install of Python 2.7 or later (e.g., python-dev)
     * Development install of curses (e.g., libncurses-dev)
     * Development install of uuid (e.g. uuid-dev)
-    * Development install of yajl (e.g. libyajl-dev)
+    * Development install of json-c (e.g. libjson-c-dev) or yajl (e.g. libyajl-dev)
     * Development install of libaio (e.g. libaio-dev) version 0.3.107 or
       greater.
     * Development install of GLib v2.0 (e.g. libglib2.0-dev)