Update zip_codes.xml

Updates to restrict postcodes to GY, inline with suggestion from contributor "Den4ik".

Author: DrJohnM

app/code/Magento/Directory/etc/zip_codes.xml

@@ -258,8 +258,8 @@
     </zip>
     <zip countryCode="GG">
         <codes>
-            <code id="pattern_1" active="true" example="AB1 2CD">^[a-zA-Z]{2}[0-9]{1}\s[0-9]{1}[a-zA-Z]{2}$</code>
-            <code id="pattern_2" active="true" example="AB12 3CD">^[a-zA-Z]{2}[0-9]{2}\s?[0-9]{1}[a-zA-Z]{2}$</code>
+            <code id="pattern_1" active="true" example="GY1 2AB">^GY[0-9]{1}\s[0-9]{1}[a-zA-Z]{2}$</code>
+            <code id="pattern_2" active="true" example="GY10 1PB">^GY[0-9]{2}\s?[0-9]{1}[a-zA-Z]{2}$</code>
         </codes>
     </zip>
     <zip countryCode="GH">