add authors

Author: alimanfoo

_posts/2019-05-02-zarr-2.3-release.md

@@ -218,3 +218,8 @@ an Xarray sprint on the Saturday. Please do say hi or [drop us a
 comment on this
 issue](https://github.com/zarr-developers/zarr/issues/396) if you'd
 like to connect and discuss anything.
+
+----
+
+Blog post written by [Alistair Miles](https://github.com/alimanfoo)
+and [John Kirkham](https://github.com/jakirkham).