Outdated to match newly certbot repo

[Daniel-Uzcategui]

Hi I tried running the build.sh and found that there the dependencies.txt on letencrypt folder no longer exists on master

[warent]

I forked this repo and got it working https://github.com/montfont/gcloud-certbot
make sure you go into the build.sh file and change the docker image tag to whatever you need (on line 21)