upgrade python versions, only run macos on 3.11

Author: bmillwood

.github/workflows/checks.yml

@@ -45,12 +45,16 @@ jobs:
       fail-fast: false
       matrix:
         python-version:
-          - "3.8"
           - "3.9"
           - "3.10"
+          - "3.11"
         runs-on:
           - ubuntu-latest
-          - macos-13 # as of 2024-05-16 macos-latest fails with MPS errors, see #598
+        include:
+          - python-version: "3.11"
+            runs-on: macos-13
+          - python-version: "3.11"
+            runs-on: macos-latest
     steps:
       - uses: actions/checkout@v3
       - name: Install Poetry
@@ -225,4 +229,4 @@ jobs:
         with:
           folder: docs/build
           clean-exclude: |
-            *.*.*/
+            *.*.*/