refactor(locale): fix en_GB postcode patterns

Author: ST-DDT

src/locales/en_GB/location/postcode_pattern.ts

@@ -1,4 +1,4 @@
 export default [
-  '{{string.alpha({ "casing": "upper" , "length": 2})}}{{string.numeric}} {{string.numeric}}{{string.alpha({ "casing": "upper" , "length": 2})}}',
-  '{{string.alpha({ "casing": "upper" , "length": 2})}}{{string.numeric(2)}} {{string.numeric}}{{string.alpha({ "casing": "upper" , "length": 2})}}',
+  '{{helpers.fromRegExp("[A-Z]{1,2}[0-9]{1,2} [0-9][ABDEFGHJLNPQRSTUWXYZ]{2}")}}',
+  '{{helpers.fromRegExp("[A-Z]{1,2}[0-9][A-Z] [0-9][ABDEFGHJLNPQRSTUWXYZ]{2}")}}',
 ];