Upgrade puppet-brewcask dependency

It looks like something has changed in the ecosystem. I started seeing
errors running `boxen`:

```
Error: Execution of 'brew boxen-latest brew-cask' returned 1: Error: No available formula with the name "brew-cask"
Error: /Stage[main]/Brewcask/Package[brew-cask]/ensure: change from absent to present failed: Execution of 'brew boxen-latest brew-cask' returned 1: Error: No available formula with the name "brew-cask"
```

And all of my `boxen::personal::osx_apps` would be skipped.

This change reflects the fact that `cask` now comes with `brew` now.

Puppetfile

@@ -38,7 +38,7 @@ github "module_data", "0.0.4", :repo => "ripienaar/puppet-module-data"
 # Core modules for a basic development environment. You can replace
 # some/most of these if you want, but it's not recommended.
 
-github "brewcask",    "0.0.6"
+github "brewcask",    "0.0.7"
 github "dnsmasq",     "2.0.1"
 github "foreman",     "1.2.0"
 github "gcc",         "3.0.2"

Puppetfile.lock

@@ -6,7 +6,7 @@ GITHUBTARBALL
 GITHUBTARBALL
   remote: boxen/puppet-brewcask
   specs:
-    brewcask (0.0.6)
+    brewcask (0.0.7)
 
 GITHUBTARBALL
   remote: boxen/puppet-dnsmasq
@@ -105,7 +105,7 @@ GITHUBTARBALL
 
 DEPENDENCIES
   boxen (= 3.11.1)
-  brewcask (= 0.0.6)
+  brewcask (= 0.0.7)
   dnsmasq (= 2.0.1)
   foreman (= 1.2.0)
   gcc (= 3.0.2)
@@ -125,4 +125,3 @@ DEPENDENCIES
   stdlib (= 4.7.0)
   sudo (= 1.0.0)
   xquartz (= 1.2.1)
-