CI: Need to setup miniconda for macOS-14

.github/workflows/build.yml

@@ -25,7 +25,7 @@ on:
 defaults:
   run:
     # default to use bash shell
-    shell: bash
+    shell: bash -el {0}
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
@@ -73,6 +73,10 @@ jobs:
           path: C:\vcpkg\installed\
         if: runner.os == 'Windows'
 
+      - name: Setup conda
+        uses: conda-incubator/setup-miniconda@v3
+        if: runner.os == 'macOS'
+
       - name: Install GMT dependencies
         run: |
           # $RUNNER_OS can be Linux, macOS or Windows