Bump immer from 3.2.1 to 4.0.1

Bumps [immer](https://github.com/immerjs/immer) from 3.2.1 to 4.0.1.
- [Release notes](https://github.com/immerjs/immer/releases)
- [Commits](https://github.com/immerjs/immer/compare/v3.2.1...v4.0.1)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

package.json

@@ -10,7 +10,7 @@
     "css": "^2.2.4",
     "flyd": "^0.2.8",
     "fuse.js": "^3.4.5",
-    "immer": "^3.2.1",
+    "immer": "^4.0.1",
     "mark.js": "^8.11.1",
     "mithril": "^2.0.4",
     "rss-parser": "^3.7.3",

yarn.lock

@@ -3777,10 +3777,10 @@ immediate@~3.0.5:
   resolved "https://registry.yarnpkg.com/immediate/-/immediate-3.0.6.tgz#9db1dbd0faf8de6fbe0f5dd5e56bb606280de69b"
   integrity sha1-nbHb0Pr43m++D13V5Wu2BigN5ps=
 
-immer@^3.2.1:
-  version "3.2.1"
-  resolved "https://registry.yarnpkg.com/immer/-/immer-3.2.1.tgz#e3070a96508ffdb7331f8bf681f2a55f8729d0cd"
-  integrity sha512-tRu/ipavNRwxKcRSUW2jOJ6cZCitHAHdI5WdH9fYfFt35PvZXJ7GmNVR0s1ATt6DGhgQJMnu3tVtZ2C/UzTUQw==
+immer@^4.0.1:
+  version "4.0.1"
+  resolved "https://registry.yarnpkg.com/immer/-/immer-4.0.1.tgz#9108c1ece7fdd7efb91d21e5eb4bac26f7c3a8ba"
+  integrity sha512-qZFpWApnbubcJ03gvWa6zUQz2OTkDc6yINdFXI1lm2IoMYsiVVMrxvfeLDURFhUGJfsQysDUjHSXYnJfMMHAwQ==
 
 immutable@^3.8.2:
   version "3.8.2"