fix(checkPkgMap): Fix lock file and map file validation check

Author: iarna

index.js

@@ -9,8 +9,6 @@ const path = require('path')
 const util = require('util')
 const yargs = require('yargs')
 
-const readFileAsync = util.promisify(fs.readFile)
-
 if (require.main === module) {
   main()
 }
@@ -36,8 +34,8 @@ function main () {
 function checkPkgMap () {
   try {
     const base = process.cwd()
-    const lock = JSON.parse(stripBOM(readFileAsync(path.join(base, 'package-lock.json'), 'utf8')))
-    const map = JSON.parse(stripBOM(readFileAsync(path.join(base, 'node_modules', '.package-map.json'), 'utf8')))
+    const lock = JSON.parse(stripBOM(fs.readFileSync(path.join(base, 'package-lock.json'), 'utf8')))
+    const map = JSON.parse(stripBOM(fs.readFileSync(path.join(base, 'node_modules', '.package-map.json'), 'utf8')))
     require('ssri').checkData(
       JSON.stringify(lock), map.lockfile_integrity, {error: true}
     )