Pin libuast to v3.3.1, to pick up libuast.a for macOS.

Part of the fix for #156.

Signed-off-by: M. J. Fromberger <[email protected]>

Author: creachadair

setup.py

@@ -15,7 +15,7 @@
 # The VERSION line is edited automatically during deployments.
 # You may change the contents of the string, but do not otherwise edit the line.
 VERSION = "3.x.x-dev"
-LIBUAST_VERSION = "v3.3.0"
+LIBUAST_VERSION = "v3.3.1"
 SDK_V1_VERSION = "v1.17.0"
 SDK_V1_MAJOR = SDK_V1_VERSION.split('.')[0]
 SDK_V2_VERSION = "v2.16.4"