Allow dashes in postal codes

In some countries, postal codes are defined with a dash in the middle,
so we're using a colon to define ranges instead. We could also use two
dots, like in Ruby ranges, but IMHO this would cause typos since people
would enter codes separated with three dots or just one dot.

spec/models/verification/residence_spec.rb

@@ -49,7 +49,7 @@ describe Verification::Residence do
 
     describe "postal code" do
       before do
-        Setting["postal_codes"] = "28001-28100,28200"
+        Setting["postal_codes"] = "28001:28100,28200,28303-455"
 
         census_data = double(valid?: true, district_code: "", gender: "")
         allow(census_data).to receive(:postal_code) { residence.postal_code }
@@ -69,6 +69,9 @@ describe Verification::Residence do
 
         residence.postal_code = "28200"
         expect(residence).to be_valid
+
+        residence.postal_code = "28303-455"
+        expect(residence).to be_valid
       end
 
       it "uses string ranges and not integer ranges" do
@@ -102,6 +105,12 @@ describe Verification::Residence do
         residence.postal_code = "28000"
         expect(residence).not_to be_valid
 
+        residence.postal_code = "28303-454"
+        expect(residence).not_to be_valid
+
+        residence.postal_code = "28303"
+        expect(residence).not_to be_valid
+
         residence.postal_code = "28101"
         expect(residence).not_to be_valid
         expect(residence.errors.count).to eq 1