Auto accept the libcudnn7 license

Of course I missed the whole section :

Use Lambda Stack in a shell script, Dockerfile, Ansible file, etc.*

LAMBDA_REPO=$(mktemp) && \
wget -O${LAMBDA_REPO} https://lambdalabs.com/static/misc/lambda-stack-repo.deb && \
sudo dpkg -i ${LAMBDA_REPO} && rm -f ${LAMBDA_REPO} && \
sudo apt-get update && …