Add link to fabric-scripts github repo
Add link to fabric-scripts github repo

Add link for the smokey-loop docs to the github repo for the 
fabric-scripts.

 This should help people to find out the prerequisites for installing 
and running the fabric scripts if they don't have it set up on their 
machine

alphagov/govuk-developer-docs,alphagov/govuk-developer-docs,alphagov/govuk-developer-docs,alphagov/govuk-developer-docs