build(deps-dev): upgrade typescript to ^4.0.2

package.json

@@ -145,7 +145,7 @@
     "sinon": "^9.0.3",
     "ts-node": "^9.0.0",
     "typedoc": "^0.18.0",
-    "typescript": "^3.9.7"
+    "typescript": "^4.0.2"
   },
   "optionalDependencies": {
     "@malept/electron-installer-flatpak": "^0.11.2",

yarn.lock

@@ -9833,11 +9833,16 @@ typedoc@^0.18.0:
     shelljs "^0.8.4"
     typedoc-default-themes "^0.10.2"
 
-typescript@^3.1.3, typescript@^3.9.7:
+typescript@^3.1.3:
   version "3.9.7"
   resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.9.7.tgz#98d600a5ebdc38f40cb277522f12dc800e9e25fa"
   integrity sha512-BLbiRkiBzAwsjut4x/dsibSTB6yWpwT5qWmC2OfuCg3GgVQCSgMs4vEctYPhsaGtd0AeuuHMkjZ2h2WG8MSzRw==
 
+typescript@^4.0.2:
+  version "4.0.2"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.0.2.tgz#7ea7c88777c723c681e33bf7988be5d008d05ac2"
+  integrity sha512-e4ERvRV2wb+rRZ/IQeb3jm2VxBsirQLpQhdxplZ2MEzGvDkkMmPglecnNDfSUBivMjP93vRbngYYDQqQ/78bcQ==
+
 uglify-js@^3.1.4:
   version "3.10.0"
   resolved "https://registry.yarnpkg.com/uglify-js/-/uglify-js-3.10.0.tgz#397a7e6e31ce820bfd1cb55b804ee140c587a9e7"