Fix the bug of when there is no default person to pronounce

package.json

@@ -1,6 +1,6 @@
 {
   "name": "say-it",
-  "version": "0.1.3",
+  "version": "0.1.4",
   "description": "Read the text you typed in command line by using Baidu tts.",
   "main": "say-it.js",
   "bin": {

say-it.js

@@ -20,7 +20,7 @@ var person = 0
 charm.pipe(process.stdout);
 
 program
-  .version('0.0.1')
+  .version('0.1')
   .command(' ', 'read the texts you typed in', {
     isDefault: true
   })
@@ -31,7 +31,8 @@ program.on('*', () => {
   if (!text || text.trim() === '') {
     return showError()
   }
-  if (!_.includes([0, 1, 2, 3, 4], Number.parseInt(program.person))) {
+
+  if (!!program.person && !_.includes([0, 1, 2, 3, 4], Number.parseInt(program.person))) {
     return showError(TEXTS.invalidPerson)
   }
   person = Number.parseInt(program.person)