Fix matrix build: use Miniconda instead of deprecated Mambaforge and conda instead of mamba

Author: quantDIY

.github/workflows/matrix-build.yml

@@ -32,19 +32,18 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Set up Mambaforge
+      - name: Set up Miniconda
         uses: conda-incubator/setup-miniconda@v3
         with:
-          miniforge-variant: Mambaforge
-          miniforge-version: latest
-          use-mamba: true
+          auto-update-conda: true
           python-version: ${{ matrix.python-version }}
+          activate-environment: quantx
           channels: conda-forge,defaults
 
       - name: Install conda-build
         shell: bash -l {0}
         run: |
-          mamba install -y conda-build anaconda-client
+          conda install -y conda-build anaconda-client
 
       - name: Build conda package
         shell: bash -l {0}
@@ -56,7 +55,7 @@ jobs:
         shell: bash -l {0}
         run: |
           # Install the built package locally to verify it works
-          mamba install -y --use-local quantx
+          conda install -y --use-local quantx
           # Verify CLI is accessible
           quantx version