Reuse dot-json helper functions (#3433)

* Reuse dot-json helper functions

* Remove unused reference to dot-json

scripts/build.js

@@ -1,5 +1,5 @@
+let { writeToPackageDotJson, getFromPackageDotJson } = require('./utils');
 let fs = require('fs');
-let DotJson = require('dot-json');
 let brotliSize = require('brotli-size');
 
 ([
@@ -92,18 +92,6 @@ function build(options) {
     }).catch(() => process.exit(1))
 }
 
-function writeToPackageDotJson(package, key, value) {
-    let dotJson = new DotJson(`./packages/${package}/package.json`)
-
-    dotJson.set(key, value).save()
-}
-
-function getFromPackageDotJson(package, key) {
-    let dotJson = new DotJson(`./packages/${package}/package.json`)
-
-    return dotJson.get(key)
-}
-
 function outputSize(package, file) {
     let size = bytesToSize(brotliSize.sync(fs.readFileSync(file)))