chore: update find-cycles to work with Python 2 or 3 (aws#10428)

I ran into a cycle issue and tried to use find-cycles to diagnose it; unfortunately, it wasn't Python 3-compatible. A quick update makes it work for either Python 2 or 3.

Apologies for the extra noise -- I've got my editor to automatically delete trailing whitespace.

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

scripts/find-cycles.py

@@ -3,44 +3,44 @@
 import sys
 import collections
 import pprint
- 
+
 def find(xs, x):
   for i, value in enumerate(xs):
     if x == value:
       return i
   return None
- 
+
 filenames = sys.argv[1:]
- 
+
 graph = collections.defaultdict(set)
 for filename in filenames:
-  with file(filename) as f:
+  with open(filename) as f:
     package_json = json.load(f)
- 
+
   for key in ['devDependencies', 'dependencies']:
     if key in package_json:
       graph[package_json['name']].update(package_json[key].keys())
- 
- 
+
+
 checked = set()
- 
+
 # Do a check for cycles for each package. This is slow but it works,
 # and it has the advantage that it can give good diagnostics.
 def check_for_cycles(package, path):
   i = find(path, package)
   if i is not None:
     cycle = path[i:] + [package]
-    print 'Cycle: %s' % ' => '.join(cycle)
+    print('Cycle: %s' % ' => '.join(cycle))
     return
- 
+
   if package in checked:
     return
- 
+
   checked.add(package)
- 
+
   deps = graph.get(package, [])
   for dep in deps:
     check_for_cycles(dep, path + [package])
- 
+
 for package in graph.keys():
   check_for_cycles(package, [])