Fix missing require in 'netlify functions' command

Author: Benaiah

src/commands/functions/index.js

@@ -1,5 +1,6 @@
 const chalk = require('chalk')
 const { Command } = require('@oclif/command')
+const { execSync } = require('child_process')
 
 function showHelp(command) {
   execSync(`netlify ${command} --help`, { stdio: [0, 1, 2] })