Install requirement file using conda with pip fallback

# Having a requirements.txt file has follows
torch==1.5.0
numpy==1.18.1

# Add channels. Last added is with the highest priorety
conda config --add channels pytorch
conda config --add channels conda-forge
conda config --add channels anaconda

# Install pip for fallback
conda install --yes pip

# Install with conda. If package installation fails, install with pip.
while read requirement; do conda install --yes $requirement || pip install $requirement; done < requirements.txt