Switch to miniforge, bump to py3.13

.github/workflows/gh-ci.yaml

@@ -30,13 +30,13 @@ jobs:
         fail-fast: false
         matrix:
           os: [macOS-latest, ubuntu-latest, windows-latest]
-          python-version: ["3.10", "3.11", "3.12"]
+          python-version: ["3.10", "3.11", "3.12", "3.13"]
           mdanalysis-version: ["latest", "develop"]
           # Manually exclude any combinations of the test matrix that can't be run 
           exclude:
             # The latest release of MDAnalysis only supports up to Python 3.11
             # so we exclude 3.12 from the test matrix (issue #20)
-            - python-version: "3.12"
+            - python-version: "3.13"
               mdanalysis-version: "latest"
 
     steps:
@@ -55,11 +55,9 @@ jobs:
         python-version: ${{ matrix.python-version }}
         environment-file: devtools/conda-envs/test_env.yaml
         add-pip-as-python-dependency: true
-
-        miniforge-variant: Mambaforge
+        miniforge-version: latest
         use-mamba: true
         channels: conda-forge, defaults
-
         activate-environment: pathsimanalysis-test
         auto-update-conda: true
         auto-activate-base: false