fix(badges): do not allow caching

Ensure README badges are not cached by github

Author: bethesque

lib/pact_broker/api/resources/badge.rb

@@ -31,6 +31,7 @@ def forbidden?
         private
 
         def to_svg
+          response.headers['Cache-Control'] = 'no-cache'
           badge_service.pact_verification_badge pact, label, initials, verification_status
         end
 

spec/lib/pact_broker/api/resources/badge_spec.rb

@@ -76,6 +76,10 @@ module Resources
             expect(subject.status).to eq 200
           end
 
+          it "does not allow caching" do
+            expect(subject.headers['Cache-Control']).to eq 'no-cache'
+          end
+
           it "returns the badge" do
             expect(subject.body).to eq "badge"
           end