Update build_package.yml

Source conda's shell scripts to make conda activate available for the current script session

Author: MagdaJuarez

.github/workflows/build_package.yml

@@ -21,8 +21,9 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip virtualenv
+          CONDA_BASE=$(conda info --base)
+          source "${CONDA_BASE}/etc/profile.d/conda.sh"
           conda env update --prune --file environment.yml 
-          conda init zsh
           conda activate coast
       - name: Shell Script Permissions
         run: |