Bump version to 3.3-rc

We decided to rename the upcoming 3.2.4 release to 3.3 to better reflect that
it is a significant feature release, and not a maintenance update.

The `3.2` branch was also renamed to `3.x` and will now be the development
branch for future 3.x releases (3.3, 3.4, etc.).

version.py

@@ -1,8 +1,8 @@
 short_name = "godot"
 name = "Godot Engine"
 major = 3
-minor = 2
-patch = 4
+minor = 3
+patch = 0
 status = "rc"
 module_config = ""
 year = 2021