Update to Immer 8

Summary: Per title, the primary change is that Immer 8 will also freeze automatically in _production_ builds as well.

Reviewed By: nikoant

Differential Revision: D25052621

fbshipit-source-id: 1cb0b083aae82992b57c4a6e9dca0a8bebe903ec

desktop/flipper-plugin/package.json

@@ -11,6 +11,7 @@
   "dependencies": {
     "@emotion/css": "^11.0.0",
     "@emotion/react": "^11.1.1",
+    "immer": "^8.0.0",
     "react-element-to-jsx-string": "^14.3.2"
   },
   "devDependencies": {
@@ -21,8 +22,7 @@
     "@ant-design/icons": "^4.2.2",
     "@testing-library/dom": "^7.26.3",
     "@testing-library/react": "^11.1.0",
-    "antd": "^4.8.0",
-    "immer": "^7.0.5"
+    "antd": "^4.8.0"
   },
   "scripts": {
     "reset": "rimraf lib *.tsbuildinfo",