Update firmware to v3.0.0a11

Also take advantage of new helper functions in firmware package.

package.json

@@ -4,7 +4,7 @@
     "private": true,
     "dependencies": {
         "@blueprintjs/core": "^3.30.1",
-        "@pybricks/firmware": "3.1.0",
+        "@pybricks/firmware": "4.1.0",
         "@pybricks/mpy-cross-v5": "^1.1.0",
         "@shopify/react-i18n": "^5.0.0",
         "@testing-library/jest-dom": "^5.8.0",
@@ -22,7 +22,6 @@
         "@types/zen-push": "^0.1.1",
         "ace-builds": "^1.4.11",
         "file-saver": "^2.0.2",
-        "jszip": "^3.5.0",
         "node-sass": "^4.14.1",
         "react": "^16.13.1",
         "react-ace": "^9.1.3",