Switch from mambaforge to miniforge in tests

Use update from PR #70.

Author: orbeckst

.github/workflows/docs.yaml

@@ -33,7 +33,7 @@ jobs:
         auto-update-conda: true
         channel-priority: flexible
         channels: conda-forge
-        miniforge-variant: Mambaforge
+        miniforge-version: latest
         use-mamba: true
 
     - name: Build and install package

.github/workflows/gh-ci.yaml

@@ -57,7 +57,7 @@ jobs:
         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