forth: update canonical reference version (#1850)

Changes made in 1.7.1 were superficial, so just updating the reference for consistency's sake.

Author: cmccandless

exercises/forth/forth_test.py

@@ -3,7 +3,7 @@
 from forth import evaluate, StackUnderflowError
 
 
-# Tests adapted from `problem-specifications//canonical-data.json` @ v1.7.0
+# Tests adapted from `problem-specifications//canonical-data.json` @ v1.7.1
 
 class ForthUtilities(unittest.TestCase):
     # Utility functions