Single startswith() call instead of multiple ones (zarr-developers#1556)

It's faster and probably more readable.

Co-authored-by: Davis Bennett <davis.v.bennett@gmail.com>
Co-authored-by: Joe Hamman <joe@earthmover.io>

zarr/_storage/store.py

@@ -221,9 +221,8 @@ def _validate_key(self, key: str):
             )
 
         if (
-            not key.startswith("data/")
-            and (not key.startswith("meta/"))
-            and (not key == "zarr.json")
+            not key.startswith(("data/", "meta/"))
+            and key != "zarr.json"
             # TODO: Possibly allow key == ".zmetadata" too if we write a
             #       consolidated metadata spec corresponding to this?
         ):