Remove unnecessary webpack targets since electron-forge decides those

webpack.main.config.js

@@ -15,7 +15,6 @@ module.exports = {
       ],
     },
   }),
-  target: 'electron-main',
   entry: './src/node/main.js',
   output: {
     path: path.resolve(__dirname, 'dist/main'),

webpack.renderer.config.js

@@ -12,7 +12,6 @@ module.exports = {
       ]
     },
   }),
-  target: 'electron-renderer',
   entry: {
     background: './src/renderer/background.js',
     overlay: './src/renderer/overlay.js',