Change Rule(replacements={...}) to additional_replacements

Author: sethmlarson

README.rst

@@ -67,7 +67,7 @@ customized :code:`unasync.Rule` instances to :code:`unasync.cmdclass_build_py()`
             # This rule's 'fromdir' is more specific so will take precedent
             # over the above rule if the path is within /ahip/tests/...
             # This rule adds an additional token replacement over the default replacements.
-            unasync.Rule("/ahip/tests/", "/hip/tests/", replacements={"ahip": "hip"}),
+            unasync.Rule("/ahip/tests/", "/hip/tests/", additional_replacements={"ahip": "hip"}),
         ])},
         ...
     )