Include the README and related files in the SDL framework

Xcode/SDL/pkg-support/resources/framework/INSTALL.md

@@ -0,0 +1,41 @@
+
+# Using this package
+
+This package contains SDL built for Xcode.
+
+To use this package in Xcode, drag `SDL3.framework` into your project.
+
+# Documentation
+
+An API reference, tutorials, and additional documentation is available at:
+
+https://wiki.libsdl.org/SDL3
+
+# Example code
+
+There are simple example programs available at:
+
+https://examples.libsdl.org/SDL3
+
+# Discussions
+
+## Discord
+
+You can join the official Discord server at:
+
+https://discord.com/invite/BwpFGBWsv8
+
+## Forums/mailing lists
+
+You can join SDL development discussions at:
+
+https://discourse.libsdl.org/
+
+Once you sign up, you can use the forum through the website or as a mailing list from your email client.
+
+## Announcement list
+
+You can sign up for the low traffic announcement list at:
+
+https://www.libsdl.org/mailing-list.php
+