Apply ruff/pyupgrade rule UP035

UP035 Import from `collections.abc` instead: `Callable`

Author: DimitriPapadopoulos

src/cffi/api.py

@@ -7,7 +7,7 @@
     callable
 except NameError:
     # Python 3.1
-    from collections import Callable
+    from collections.abc import Callable
     callable = lambda x: isinstance(x, Callable)
 
 try: