Do not use macos-12 in GitHub Actions

.github/workflows/conda-forge-ci.yml

@@ -15,24 +15,18 @@ jobs:
     strategy:
       matrix:
         build_type: [Release]
-        os: [ubuntu-latest, windows-2019, macos-14, macos-12]
+        os: [ubuntu-latest, windows-2019, macos-latest]
         imgui: [mamba, vendored]
       fail-fast: false
 
     steps:
     - uses: actions/checkout@v2
 
     - uses: conda-incubator/setup-miniconda@v3
-      if: matrix.os != 'macos-14'
       with:
         miniforge-variant: Mambaforge
         miniforge-version: latest
 
-    - uses: conda-incubator/setup-miniconda@v3
-      if: matrix.os == 'macos-14'
-      with:
-        installer-url: https://github.com/conda-forge/miniforge/releases/download/23.11.0-0/Mambaforge-23.11.0-0-MacOSX-arm64.sh
-
     - name: Dependencies
       shell: bash -l {0}
       run: |