Restore support for python 3.8

Reduce minimum xarray to 2023.1.0

Python 3.8 is EoL, but only just: Oct 7, 2024.

Author: bendudson

.github/workflows/master.yml

@@ -20,7 +20,7 @@ jobs:
     if: always()
     strategy:
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.x"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.x"]
       fail-fast: false
 
     steps:

.github/workflows/pythonpackage.yml

@@ -20,7 +20,7 @@ jobs:
     if: always()
     strategy:
       matrix:
-        python-version: ["3.9", "3.10", "3.x"]
+        python-version: ["3.8", "3.9", "3.10", "3.x"]
       fail-fast: false
 
     steps:
@@ -48,7 +48,7 @@ jobs:
     if: always()
     strategy:
       matrix:
-        python-version: ["3.9"]
+        python-version: ["3.8"]
       fail-fast: false
 
     steps:

pyproject.toml

@@ -33,7 +33,7 @@ classifiers = [
 ]
 requires-python = ">=3.8"
 dependencies = [
-    "xarray>=2024.7.0",
+    "xarray>=2023.01.0",
     "boutdata>=0.1.4",
     "dask[array]>=2.10.0",
     "gelidum>=0.5.3",