Update pebble shell for HTTPS. (#67)
Update pebble shell for HTTPS. (#67)

The Pebble API is now only accessible over HTTPS. This commit updates
the pebble shell to use HTTPS & to trust the MiniCA pebble CA by
default.
shred/pebble,letsencrypt/pebble,shred/pebble,letsencrypt/pebble,letsencrypt/pebble