Upgrade Electron to 39.2.7 to fix macOS Tahoe GPU performance regression (#931)

backend/src/ConfigStorage.ts

@@ -9,7 +9,7 @@ export default class ConfigStorage {
   private file: string
   private database: any
   private rpc: Rpc
-  
+
   constructor(file: string, rpc: Rpc) {
     this.file = file
     this.rpc = rpc

backend/src/Model/Base64Message.ts

@@ -82,7 +82,7 @@ export class Base64Message {
 
     let str: string = ''
     buf.forEach(element => {
-      let hex = element.toString(16).toUpperCase()
+      const hex = element.toString(16).toUpperCase()
       str += `0x${hex.length < 2 ? '0' + hex : hex} `
     })
     return str.trimRight()