fix(isMobilePhone): add support for en-SG +656 (#1337)

Author: chungweileong94

src/lib/isMobilePhone.js

@@ -38,7 +38,7 @@ const phones = {
   'en-NZ': /^(\+?64|0)[28]\d{7,9}$/,
   'en-PK': /^((\+92)|(0092))-{0,1}\d{3}-{0,1}\d{7}$|^\d{11}$|^\d{4}-\d{7}$/,
   'en-RW': /^(\+?250|0)?[7]\d{8}$/,
-  'en-SG': /^(\+65)?[89]\d{7}$/,
+  'en-SG': /^(\+65)?[689]\d{7}$/,
   'en-SL': /^(?:0|94|\+94)?(7(0|1|2|5|6|7|8)( |-)?\d)\d{6}$/,
   'en-TZ': /^(\+?255|0)?[67]\d{8}$/,
   'en-UG': /^(\+?256|0)?[7]\d{8}$/,

test/validators.js

@@ -5512,6 +5512,7 @@ describe('Validators', () => {
           '98765432',
           '+6587654321',
           '+6598765432',
+          '+6565241234',
         ],
         invalid: [
           '987654321',