adding a more minimal conda install

[shimwell]

could make a conda install for the whole package now that cadquery is on pip and the environment can be resolved.

curl -L -O https://github.com/conda-forge/miniforge/releases/latest/download/Miniforge-pypy3-Linux-x86_64.sh
bash Miniforge-pypy3-Linux-x86_64.sh

conda create --name openmc_0.13.3 python=3.10
conda activate openmc_0.13.3

conda install -c conda-forge openmc=0.13.3

pip install openmc_data
download_nndc -r b8.0
download_nndc_chain -r b8.0

echo 'export OPENMC_CHAIN_FILE=/home/jshimwell/chain-nndc-b8.0.xml' >> ~/.bashrc 
echo 'export OPENMC_CROSS_SECTIONS=/home/jshimwell/nndc-b8.0-hdf5/endfb-viii.0-hdf5/cross_sections.xml' >> ~/.bashrc