Update patch to Python 3.13.1.

Makefile

@@ -18,7 +18,7 @@ BUILD_NUMBER=custom
 # of a release cycle, as official binaries won't be published.
 # PYTHON_MICRO_VERSION is the full version number, without any alpha/beta/rc suffix. (e.g., 3.10.0)
 # PYTHON_VER is the major/minor version (e.g., 3.10)
-PYTHON_VERSION=3.14.0a2
+PYTHON_VERSION=3.13.1
 PYTHON_PKG_VERSION=$(PYTHON_VERSION)
 PYTHON_MICRO_VERSION=$(shell echo $(PYTHON_VERSION) | grep -Eo "\d+\.\d+\.\d+")
 PYTHON_PKG_MICRO_VERSION=$(shell echo $(PYTHON_PKG_VERSION) | grep -Eo "\d+\.\d+\.\d+")

README.rst

@@ -4,15 +4,15 @@ Python Apple Support
 This is a meta-package for building a version of Python that can be embedded
 into a macOS, iOS, tvOS or watchOS project.
 
-**This branch builds a packaged version of Python 3.14**.
+**This branch builds a packaged version of Python 3.13**.
 Other Python versions are available by cloning other branches of the main
 repository:
 
 * `Python 3.9 <https://github.com/beeware/Python-Apple-support/tree/3.9>`__
 * `Python 3.10 <https://github.com/beeware/Python-Apple-support/tree/3.10>`__
 * `Python 3.11 <https://github.com/beeware/Python-Apple-support/tree/3.11>`__
 * `Python 3.12 <https://github.com/beeware/Python-Apple-support/tree/3.12>`__
-* `Python 3.13 <https://github.com/beeware/Python-Apple-support/tree/3.13>`__
+* `Python 3.14 <https://github.com/beeware/Python-Apple-support/tree/3.14>`__
 
 It works by downloading, patching, and building a fat binary of Python and
 selected pre-requisites, and packaging them as frameworks that can be