Change http link to https link.

Author: HonkingGoose

book/06-github/sections/3-maintaining.asc

@@ -89,7 +89,7 @@ You could technically merge in the Pull Request work with something like this:
 
 [source,console]
 ----
-$ curl http://github.com/tonychacon/fade/pull/1.patch | git am
+$ curl https://github.com/tonychacon/fade/pull/1.patch | git am
 ----
 
 ===== Collaborating on the Pull Request