Update "check for update" to use master tag

Previously we were using the `latest` tag to trigger builds on Docker
Hub.

Author: johnallen3d

VERSION

@@ -1 +1 @@
-1.2.0
+1.2.1

bin/release

@@ -19,7 +19,7 @@ fi
 
 NIB_VERSION=$(cat VERSION)
 LATEST="$(
-  curl --silent https://raw.githubusercontent.com/technekes/nib/latest/VERSION
+  curl --silent https://raw.githubusercontent.com/technekes/nib/master/VERSION
 )"
 
 if [[ $(git status | grep VERSION) ]]; then

lib/nib/check_for_update.rb

@@ -16,7 +16,7 @@ def self.installed
   end
 
   def self.latest
-    url = 'https://raw.githubusercontent.com/technekes/nib/latest/VERSION'
+    url = 'https://raw.githubusercontent.com/technekes/nib/master/VERSION'
 
     Net::HTTP.get(URI.parse(url)).chomp
   end