chore(ci): switch to miniforge

.github/workflows/build-test.yml

@@ -10,6 +10,11 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
+# Required for miniconda to activate conda
+defaults:
+  run:
+    shell: bash -l {0}
+
 jobs:
   build:
     strategy:
@@ -21,11 +26,6 @@ jobs:
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 30
 
-    # Required for miniconda to activate conda
-    defaults:
-      run:
-        shell: bash -l {0}
-
     steps:
       - uses: actions/checkout@v4
 
@@ -34,14 +34,16 @@ jobs:
         with:
           auto-update-conda: true
           python-version: ${{ matrix.python-version }}
-          miniforge-variant: Mambaforge
-          use-mamba: true
+          miniforge-version: latest
+
+      - name: Check active Python version
+        run: python -c "import sys; assert '.'.join(str(s) for s in sys.version_info[:2]) == '${{ matrix.python-version }}', f'{version} incorrect!'"
 
       - name: Install ROOT
         if: matrix.python-version == 3.8  &&  runner.os != 'macOS'  &&  runner.os != 'Windows'
         run: |
           conda env list
-          mamba install root
+          conda install root
           conda list
 
       - name: Install sshd for fsspec ssh tests
@@ -59,7 +61,7 @@ jobs:
         if: runner.os != 'macOS'  &&  runner.os != 'Windows'
         run: |
           conda env list
-          mamba install xrootd
+          conda install xrootd
           conda list
 
       - name: Pip install the package