ci: use setup-miniconda@v3

Author: fabinsch

.github/workflows/ci-linux-osx-win-conda.yml

@@ -57,22 +57,14 @@ jobs:
       with:
         submodules: recursive
 
-    - uses: conda-incubator/setup-miniconda@v2
-      if: matrix.os != 'macos-14'
+    - uses: conda-incubator/setup-miniconda@v3
       with:
-        miniforge-variant: Mambaforge
+        miniforge-variant: Miniforge3
         miniforge-version: latest
         channels: conda-forge
         python-version: "3.10"
         activate-environment: proxsuite
 
-    - uses: conda-incubator/setup-miniconda@v3
-      if: matrix.os == 'macos-14'
-      with:
-        channels: conda-forge
-        python-version: "3.10"
-        activate-environment: proxsuite
-        installer-url: https://github.com/conda-forge/miniforge/releases/download/23.11.0-0/Mambaforge-23.11.0-0-MacOSX-arm64.sh
 
     - name: Install dependencies [Conda]
       shell: bash -l {0}