Update CI workflow

Move run onto Ubuntu 24.04 and v6 of checkout and setup-python

Author: drsteve

.github/workflows/ci.yml

@@ -16,22 +16,28 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - python-version: "3.8"
-            os: ubuntu-20.04
+          - python-version: "3.10"
+            os: ubuntu-24.04
             piplist: "numpy matplotlib"
-          - python-version: "3.9"
-            os: ubuntu-20.04
+          - python-version: "3.11"
+            os: ubuntu-24.04
             piplist: "numpy matplotlib"
             dep-strategy: "oldest"
-          - python-version: "3.10"
-            os: ubuntu-20.04
+          - python-version: "3.12"
+            os: ubuntu-24.04
             piplist: "numpy matplotlib"
-          - python-version: "3.10"
-            os: ubuntu-20.04
+          - python-version: "3.13"
+            os: ubuntu-24.04
+            piplist: "numpy matplotlib spacepy"
+          - python-version: "3.14"
+            os: ubuntu-24.04
+            piplist: "numpy matplotlib"
+          - python-version: "3.14"
+            os: ubuntu-24.04
             piplist: "numpy matplotlib spacepy"
     steps:
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v6
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
@@ -45,7 +51,7 @@ jobs:
 # Per https://github.com/actions/checkout/issues/15, this gets the MERGE
 # commit of the PR, not just the tip of the PR.
     - name: checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v6
     - name: Install and run tests
       working-directory: ${{ github.workspace }}
       run: |
@@ -55,7 +61,7 @@ jobs:
   all-tests:
     name: All tests
     if: ${{ always() }}
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-24.04
     needs: test
     steps:
       - name: Check test matrix status