fix windows build error

package.json

@@ -8,7 +8,7 @@
   "homepage": "./",
   "scripts": {
     "start": "concurrently -k \"BROWSER=none PORT=3001 react-scripts start\" \"wait-on http://localhost:3001 && electron .\"",
-    "icon-gen": "mkdir -p icon-build && svg2png src/icon.svg -o ./icon-build/app-512.png -w 512 -h 512 && mkdir -p icns-build && icon-gen -i src/icon.svg -o ./icns-build --icns --icns-sizes 512,1024 && mkdir -p build-resources/appx && npx svg2png src/icon.svg --output=build-resources/appx/StoreLogo.png --width=50 --height=50 && npx svg2png src/icon.svg --output=build-resources/appx/Square150x150Logo.png --width=300 --height=300 && npx svg2png src/icon.svg --output=build-resources/appx/Square44x44Logo.png --width=44 --height=44 && npx svg2png src/icon.svg --output=build-resources/appx/Wide310x150Logo.png --width=620 --height=300",
+    "icon-gen": "mkdirp icon-build && svg2png src/icon.svg -o ./icon-build/app-512.png -w 512 -h 512 && mkdirp icns-build && icon-gen -i src/icon.svg -o ./icns-build --icns --icns-sizes 512,1024 && mkdirp build-resources/appx && npx svg2png src/icon.svg --output=build-resources/appx/StoreLogo.png --width=50 --height=50 && npx svg2png src/icon.svg --output=build-resources/appx/Square150x150Logo.png --width=300 --height=300 && npx svg2png src/icon.svg --output=build-resources/appx/Square44x44Logo.png --width=44 --height=44 && npx svg2png src/icon.svg --output=build-resources/appx/Wide310x150Logo.png --width=620 --height=300",
     "build": "yarn icon-gen && react-scripts build",
     "test": "react-scripts test",
     "eject": "react-scripts eject",
@@ -54,6 +54,7 @@
     "i18next": "^19.3.2",
     "icon-gen": "^2.0.0",
     "lodash": "^4.17.13",
+    "mkdirp": "^1.0.3",
     "moment": "^2.18.1",
     "mousetrap": "^1.6.1",
     "p-map": "^3.0.0",

yarn.lock

@@ -8295,6 +8295,11 @@ mkdirp@0.5.1, mkdirp@^0.5.1, mkdirp@~0.5.1:
   dependencies:
     minimist "0.0.8"
 
+mkdirp@^1.0.3:
+  version "1.0.3"
+  resolved "https://registry.yarnpkg.com/mkdirp/-/mkdirp-1.0.3.tgz#4cf2e30ad45959dddea53ad97d518b6c8205e1ea"
+  integrity sha512-6uCP4Qc0sWsgMLy1EOqqS/3rjDHOEnsStVr/4vtAIK2Y5i2kA7lFFejYrpIyiN9w0pYf4ckeCYT9f1r1P9KX5g==
+
 moment@^2.18.1:
   version "2.20.1"
   resolved "https://registry.yarnpkg.com/moment/-/moment-2.20.1.tgz#d6eb1a46cbcc14a2b2f9434112c1ff8907f313fd"