update requirements with released version of xarray

Author: TomNicholas

README.md

@@ -6,9 +6,8 @@ Interface for using [cubed](https://github.com/tomwhite/cubed) with [xarray](htt
 
 ## Requirements
 
-Cubed version >v0.6.0
-
-[Xarray pull request #7019](https://github.com/pydata/xarray/pull/7019)
+- Cubed version >=0.6.3
+- Xarray version >=2023.05.0
 
 ## Installation
 
@@ -29,7 +28,8 @@ Xarray objects backed by cubed arrays can be created either by:
 In (2) and (3) the choice to use `cubed.Array` instead of `dask.array.Array` is made by passing the keyword argument `chunked_array_type='cubed'`.
 To pass arguments to the constructor of `cubed.Array` then pass them via the dictionary `from_array_kwargs`, e.g. `from_array_kwargs={'spec': cubed.Spec(max_mem=2_000_000)}`.
 
-If cubed and cubed-xarray are installed but dask is not, then specifying the parallel array type to use is not necessary.
+If cubed and cubed-xarray are installed but dask is not, then specifying the parallel array type to use is not necessary, 
+as the entrypoints system will then default to the only chunked parallel backend available (i.e. cubed).
 
 ## Tests
 

pyproject.toml

@@ -22,8 +22,8 @@ classifiers = [
 requires-python = ">=3.9"
 dependencies = [
     "numpy >= 1.17",
-    "xarray >= 0.16.1",
-    "cubed >= 0.6.0",
+    "xarray >= 2023.05.0",
+    "cubed >= 0.6.3",
 ]
 
 [project.urls]