avoid size limit when converting between strings and integers

ValueError: Exceeds the limit (4300) for integer string conversion;
use sys.set_int_max_str_digits() to increase the limit

spyne/test/interop/server/_service.py

@@ -340,7 +340,7 @@ def complex_return():
 
     @srpc(_returns=Integer)
     def huge_number():
-        return 2**int(1e5)
+        return 2**int(1e4)
 
     @srpc(_returns=String)
     def long_string():