Update phone regex for Zambia (#2482)

Author: sonikishan

src/lib/isMobilePhone.js

@@ -70,7 +70,7 @@ const phones = {
   'en-UG': /^(\+?256|0)?[7]\d{8}$/,
   'en-US': /^((\+1|1)?( |-)?)?(\([2-9][0-9]{2}\)|[2-9][0-9]{2})( |-)?([2-9][0-9]{2}( |-)?[0-9]{4})$/,
   'en-ZA': /^(\+?27|0)\d{9}$/,
-  'en-ZM': /^(\+?26)?09[567]\d{7}$/,
+  'en-ZM': /^(\+?26)?0[79][567]\d{7}$/,
   'en-ZW': /^(\+263)[0-9]{9}$/,
   'en-BW': /^(\+?267)?(7[1-8]{1})\d{6}$/,
   'es-AR': /^\+?549(11|[2368]\d)\d{8}$/,

test/validators.test.js

@@ -8777,13 +8777,16 @@ describe('Validators', () => {
           '+260966684590',
           '+260976684590',
           '260976684590',
+          '+260779493521',
+          '+260760010936',
         ],
         invalid: [
           '12345',
           '',
           'Vml2YW11cyBmZXJtZtesting123',
           '010-38238383',
           '966684590',
+          '760010936',
         ],
       },
       {