With SASL set use_sasl to 1

Due to the fact the the php inis are copied in the buildpack from
the stack image to the deployment image, introducing memcached.use_sasl=1
gets more complicated. use_sasl is not set to 1 by default.

cacert.pem from https://github.com/certifi/python-certifi/tree/ae3ca7b3d7451a28bb340acf7bb2fd69574fbc3b/certifi