Docs: More build and packaging

Author: ax3l

docs/source/developers/testing.rst

@@ -12,7 +12,8 @@ In order to run our tests, you need to have a few :ref:`Python packages installe
 
 .. code-block:: sh
 
-   python3 -m pip install -U pip setuptools wheel pytest
+   python3 -m pip install -U pip
+   python3 -m pip install -U build packaging setuptools wheel pytest
    python3 -m pip install -r requirements.txt
 
 

docs/source/install/cmake.rst

@@ -33,7 +33,8 @@ On your development machine, :ref:`follow the instructions here <install-depende
 
    .. code-block:: bash
 
-      python3 -m pip install -U pip setuptools wheel pytest
+      python3 -m pip install -U pip
+      python3 -m pip install -U build packaging setuptools wheel pytest
       python3 -m pip install -U -r requirements.txt
 
 

spack.yaml

@@ -25,8 +25,10 @@ spack:
   - cmake
   - mpi
   - python
+  - py-build
   - py-mpi4py
   - py-numpy
+  - py-packaging
   - py-pip
   - py-setuptools
   - py-wheel