Python 3.10.0a0 (GH-20198)

diff --git a/configure.ac b/configure.ac
index 497d7c1..84d1f00 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3,7 +3,7 @@
 dnl ***********************************************
 
 # Set VERSION so we only need to edit in one place (i.e., here)
-m4_define(PYTHON_VERSION, 3.9)
+m4_define(PYTHON_VERSION, 3.10)
 
 AC_PREREQ([2.69])