note pep584 change in README

MarcoGorelli · MarcoGorelli · commit 88b8054b8d8b · 2021-05-15T08:30:31.000+01:00
diff --git a/README.md b/README.md
@@ -515,6 +515,19 @@ Availability:
 ```
 
 
+### merge dicts using union operator (pep 584)
+
+Availability:
+- `--py39-plus` is passed on the commandline.
+
+```diff
+ x = {"a": 1}
+ y = {"b": 2}
+-z = {**x, **y}
++z = x | y
+```
+
+
 ### pep 585 typing rewrites
 
 Availability:
