Update patch to Python 3.9.20.

Author: freakboy3742

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=3.9.19
+PYTHON_VERSION=3.9.20
 PYTHON_PKG_VERSION=3.9.13
 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+")