Actions: Use pip install -e .[module] for module tests

Author: simmsa

.github/workflows/main.yml

@@ -433,7 +433,7 @@ jobs:
       - name: Install MHKiT with optional dependency
         run: |
           python -m pip install --upgrade pip
-          pip install "mhkit[${{ matrix.module }}]"
+          pip install -e ".[${{ matrix.module }}]"
           pip install pytest
 
       - name: Reinstall h5py and netCDF4 with system libraries