Add 3.12 and 3.13 to installation docs

Author: instinct-vfx

docs/source/installation.rst

@@ -7,7 +7,7 @@ Installation Script
 
 To install rez, you will need:
 
-1. Python 3.7 or above. We support 3.7, 3.8, 3.9, 3.10 and 3.11.
+1. Python 3.7 or above. We support 3.7, 3.8, 3.9, 3.10, 3.11, 3.12 and 3.13.
    The python interpreter you use to run the install script will be the interpreter
    used by rez itself.
 2. The source code. You can get it by either cloning the `repository <https://github.com/AcademySoftwareFoundation/rez>`_