Forward port macOS installer updates from 3.7/3.8/3.9 (GH-21132)

diff --git a/Mac/BuildScript/resources/Welcome.rtf b/Mac/BuildScript/resources/Welcome.rtf
index bf6aebe..cadfbf6 100644
--- a/Mac/BuildScript/resources/Welcome.rtf
+++ b/Mac/BuildScript/resources/Welcome.rtf
@@ -1,5 +1,5 @@
-{\rtf1\ansi\ansicpg1252\cocoartf1671\cocoasubrtf600
-\cocoascreenfonts1{\fonttbl\f0\fswiss\fcharset0 Helvetica;\f1\fswiss\fcharset0 Helvetica-Bold;\f2\fmodern\fcharset0 CourierNewPSMT;
+{\rtf1\ansi\ansicpg1252\cocoartf2513
+\cocoascreenfonts1\cocoatextscaling0\cocoaplatform0{\fonttbl\f0\fswiss\fcharset0 Helvetica;\f1\fswiss\fcharset0 Helvetica-Bold;\f2\fmodern\fcharset0 CourierNewPSMT;
 }
 {\colortbl;\red255\green255\blue255;}
 {\*\expandedcolortbl;;}
@@ -26,5 +26,5 @@
 \
 
 \f1\b NOTE: 
-\f0\b0 This is an alpha test preview of Python 3.9.0, the next feature release of Python 3.  It is not intended for production use.\
+\f0\b0 This is an alpha test preview of Python 3.10.0, the next feature release of Python 3.  It is not intended for production use.\
 }
\ No newline at end of file