Repeated installs of Drupal minimum profile to with PHP 5.6 and PHP 7

gistfile1.txt

echo "php_version: 5.6" >> pantheon.yml

git add pantheon.yml
git commit -m 'Setting php 5.6'
git push

sleep 30
for i in $(seq 20); do
  echo "Site install $i in PHP 5.6"
  terminus drush "si minimal -y"
done

sleep 15
echo "php_version: 7.0" >> pantheon.yml

git add pantheon.yml
git commit -m 'Setting php 7.0'
git push

sleep 60

for i in $(seq 20); do
  echo "Site install $i in PHP 7.0"
  terminus drush "si minimal -y"
done