[Changed] Add the -vendor-only flag to dep-ensure calls

[Finish #155050350]

Signed-off-by: Ryan Collins <rcollins@pivotal.io>

Author: xtreme-shane-lattanzio

lib/license_finder/package_managers/dep.rb

@@ -23,7 +23,7 @@ def self.takes_priority_over
     end
 
     def self.prepare_command
-      'dep ensure'
+      'dep ensure -vendor-only'
     end
 
     def self.package_management_command

spec/lib/license_finder/package_managers/dep_spec.rb

@@ -32,7 +32,7 @@ module LicenseFinder
 
     describe '.prepare_command' do
       it 'returns the correct prepare method' do
-        expect(described_class.prepare_command).to eq('dep ensure')
+        expect(described_class.prepare_command).to eq('dep ensure -vendor-only')
       end
     end