Allow date of birth to be supplied as a Date or Time

Forcing a String parameter is a bit restrictive, particularly when using
a framework that automatically converts dates as they come out of
database (e.g. Rails / ActiveRecord).

The user shouldn't need to get involved in the implementation details
given how easy it is for the library to convert to a String

lib/eml/uk/payload/card/register.rb

@@ -43,8 +43,9 @@ def city=(city)
             @city = city
           end
 
-          sig { params(dob: String).void }
+          sig { params(dob: T.any(Date, String, Time)).void }
           def dob=(dob)
+            dob = dob.strftime("%m%d%Y") if dob.respond_to?(:strftime)
             validate_dob(dob)
             @dob = dob
           end

lib/eml/version.rb

@@ -2,5 +2,5 @@
 # frozen_string_literal: true
 
 module EML
-  VERSION = "2.1.7"
+  VERSION = "2.1.8"
 end

spec/uk/resources/card_spec.rb

@@ -65,13 +65,32 @@
     context "when the DOB is in the wrong format" do
       it "raises an ArgumentError" do
         payload[:dob] = "31012000"
-        cassette = "uk/card/register/dob"
-        EML::Helpers::VCR.with_cassette(cassette) do
+        EML::Helpers::VCR.with_cassette("uk/card/register/dob_string") do
           expect { described_class.register(id: card_id, payload: payload) }.
             to raise_error(ArgumentError)
         end
       end
     end
+
+    context "when the DOB is a Date object" do
+      it "registers the card" do
+        payload[:dob] = Date.parse("2000-01-31")
+        EML::Helpers::VCR.with_cassette("uk/card/register/dob_date") do
+          response = described_class.register(id: card_id, payload: payload)
+          expect(response.success?).to be true
+        end
+      end
+    end
+
+    context "when the DOB is a Time object" do
+      it "registers the card" do
+        payload[:dob] = Time.parse("2000-01-31")
+        EML::Helpers::VCR.with_cassette("uk/card/register/dob_date") do
+          response = described_class.register(id: card_id, payload: payload)
+          expect(response.success?).to be true
+        end
+      end
+    end
   end
 
   describe ".reload" do