addons.coverty_scan.project: accept a string directly

SPEC.md

@@ -32,7 +32,7 @@ Note that stricitly speaking Travis CI might not have the same understanding of
 **Expected format:** String or encrypted string.
 
 #### `addons.coverty_scan.project`
-**Expected format:** Key value mapping.
+**Expected format:** Key value mapping, or strings or encrypted strings.
 
 #### `addons.coverty_scan.project.name`
 **This setting is required!**

lib/travis/yaml/nodes/addons.rb

@@ -14,6 +14,7 @@ def visit_scalar(visitor, type, value, implicit = true)
       class CovertyScan < Addon
         class Project < Mapping
           map :name, to: Scalar[:str, :secure], required: true
+          auto_prefix :name
         end
 
         map :project, to: Project

spec/nodes/addons_spec.rb

@@ -14,6 +14,11 @@ def addons(input)
         config = addons(coverty_scan: { project: { name: :foo } })
         expect(config.coverty_scan.project.name).to be == "foo"
       end
+
+      example do
+        config = addons(coverty_scan: { project: :foo })
+        expect(config.coverty_scan.project.name).to be == "foo"
+      end
     end
 
     context 'firefox' do