Update requirements txt file

update_requirements.sh

update-requirements: VENV := /tmp/update-requirements-venv
update-requirements: ## updates requirements
    @if [ -d $(VENV) ]; then rm -rf $(VENV); fi
    @mkdir -p $(VENV)
    $(PYTHON) -m venv $(VENV)
    $(PIP) install --upgrade pip
    $(PIP) install -r unpinned_requirements.txt
    echo "Created by update-requirements. Do not edit." > requirements.txt
    $(PIP) freeze | grep -v pkg-resources==0.0.0 >> requirements.txt