Add installation procedures to package.yml instructions

.github/workflows/package.yml

@@ -52,6 +52,7 @@ jobs:
           conda activate hexrd
           conda install --override-channels -c conda-forge anaconda-client conda-build conda
 
+          python install_build_dependencies.py
       # This is need to ensure ~/.profile or ~/.bashrc are used so the activate
       # command works.
       shell: bash -l {0}