chore: bump is-plain-obj from 3.0.0 to 4.1.0

Bumps [is-plain-obj](https://github.com/sindresorhus/is-plain-obj) from 3.0.0 to 4.1.0.
- [Release notes](https://github.com/sindresorhus/is-plain-obj/releases)
- [Commits](sindresorhus/is-plain-obj@v3.0.0...v4.1.0)

---
updated-dependencies:
- dependency-name: is-plain-obj
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

packages/rich-text-types/package.json

@@ -25,7 +25,7 @@
     "test": "jest"
   },
   "dependencies": {
-    "is-plain-obj": "^3.0.0"
+    "is-plain-obj": "^4.1.0"
   },
   "devDependencies": {
     "@types/jest": "^29.5.12",

yarn.lock

@@ -4816,10 +4816,10 @@ is-plain-obj@^2.0.0:
   resolved "https://registry.yarnpkg.com/is-plain-obj/-/is-plain-obj-2.1.0.tgz#45e42e37fccf1f40da8e5f76ee21515840c09287"
   integrity sha512-YWnfyRwxL/+SsrWYfOpUtz5b3YD+nyfkHvjbcanzk8zgyO4ASD67uVMRt8k5bM4lLMDnXfriRhOpemw+NfT1eA==
 
-is-plain-obj@^3.0.0:
-  version "3.0.0"
-  resolved "https://registry.yarnpkg.com/is-plain-obj/-/is-plain-obj-3.0.0.tgz#af6f2ea14ac5a646183a5bbdb5baabbc156ad9d7"
-  integrity sha512-gwsOE28k+23GP1B6vFl1oVh/WOzmawBrKwo5Ev6wMKzPkaXaCDIQKzLnvsA42DRlbVTWorkgTKIviAKCWkfUwA==
+is-plain-obj@^4.1.0:
+  version "4.1.0"
+  resolved "https://registry.yarnpkg.com/is-plain-obj/-/is-plain-obj-4.1.0.tgz#d65025edec3657ce032fd7db63c97883eaed71f0"
+  integrity sha512-+Pgi+vMuUNkJyExiMBt5IlFoMyKnr5zhJ4Uspz58WOhBF5QoIZkFyNHIbBAtHwzVAgk5RtndVNsDRN61/mmDqg==
 
 is-plain-object@^2.0.4:
   version "2.0.4"