Fix state.json not pretty printed (#4943)

* state.json format

Since 9774031 the state.json file is not formatted anymore, it's just 1 line.

* Update state.js

Co-authored-by: Koen Kanters <koenkanters94@gmail.com>

lib/state.js

@@ -3,7 +3,6 @@ const data = require('./util/data');
 const settings = require('./util/settings');
 const fs = require('fs');
 const objectAssignDeep = require('object-assign-deep');
-const stringify = require('json-stable-stringify-without-jsonify');
 
 const saveInterval = 1000 * 60 * 5; // 5 minutes
 
@@ -57,7 +56,7 @@ class State {
     save() {
         if (settings.get().advanced.cache_state_persistent) {
             logger.debug(`Saving state to file ${this.file}`);
-            const json = stringify(this.state, null, 4);
+            const json = JSON.stringify(this.state, null, 4);
             try {
                 fs.writeFileSync(this.file, json, 'utf8');
             } catch (e) {