Change the version to 2.2a0. This may look strange, but indicates

it's 2.2 before the first alpha release.

Include/patchlevel.h

@@ -20,16 +20,16 @@
 
 /* Version parsed out into numeric values */
 #define PY_MAJOR_VERSION	2
-#define PY_MINOR_VERSION	1
+#define PY_MINOR_VERSION	2
 #define PY_MICRO_VERSION	0
-#define PY_RELEASE_LEVEL	PY_RELEASE_LEVEL_FINAL
+#define PY_RELEASE_LEVEL	PY_RELEASE_LEVEL_ALPHA
 #define PY_RELEASE_SERIAL	0
 
 /* Version as a string */
-#define PY_VERSION		"2.1"
+#define PY_VERSION		"2.2a0"
 
 /* Historic */
-#define PATCHLEVEL		"2.1"
+#define PATCHLEVEL		"2.2a0"
 
 /* Version as a single 4-byte hex number, e.g. 0x010502B2 == 1.5.2b2.
    Use this for numeric comparisons, e.g. #if PY_VERSION_HEX >= ... */