remove macos13 conda from the CI

Author: carlocamilloni

.github/workflows/ci.yml

@@ -308,7 +308,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-22.04 , macos-13, macos-14 ]
+        os: [ubuntu-22.04, macos-14 ]
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v4