Make sure setuptools is compatible with PEP 639

PEP 639 requires setuptools ≥ 77.

It seems customary to require setuptools ≥ 77.0.2 which irons out some
bugs related to PEP 639 support.

Author: DimitriPapadopoulos

pyproject.toml

@@ -97,7 +97,7 @@ dask = "xarray.namedarray.daskmanager:DaskManager"
 
 [build-system]
 build-backend = "setuptools.build_meta"
-requires = ["setuptools>=42", "setuptools-scm>=7"]
+requires = ["setuptools>=77.0.2", "setuptools-scm>=7"]
 
 [tool.setuptools.packages.find]
 include = ["xarray*"]