Change minimum Python version of upstream CI to 3.11 to match Zarr

Author: tomwhite

.github/workflows/upstream.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.10", "3.11"]
+        python-version: ["3.11", "3.12"]
 
     steps:
     - uses: actions/checkout@v2