remove unused packages

packages/core/package.json

@@ -12,13 +12,9 @@
     "dist"
   ],
   "dependencies": {
-    "@types/clone-deep": "^4.0.1",
     "@types/prosemirror-dropcursor": "^1.0.0",
     "@types/prosemirror-gapcursor": "^1.0.1",
     "@types/prosemirror-schema-list": "^1.0.1",
-    "clone-deep": "^4.0.1",
-    "collect.js": "^4.28.2",
-    "deepmerge": "^4.2.2",
     "prosemirror-commands": "^1.1.3",
     "prosemirror-dropcursor": "^1.3.2",
     "prosemirror-gapcursor": "^1.1.5",

yarn.lock

@@ -2198,11 +2198,6 @@
   dependencies:
     defer-to-connect "^1.0.1"
 
-"@types/clone-deep@^4.0.1":
-  version "4.0.1"
-  resolved "https://registry.yarnpkg.com/@types/clone-deep/-/clone-deep-4.0.1.tgz#7c488443ab9f571cd343d774551b78e9264ea990"
-  integrity sha512-bdkCSkyVHsgl3Goe1y16T9k6JuQx7SiDREkq728QjKmTZkGJZuS8R3gGcnGzVuGBP0mssKrzM/GlMOQxtip9cg==
-
 "@types/estree@*":
   version "0.0.45"
   resolved "https://registry.yarnpkg.com/@types/estree/-/estree-0.0.45.tgz#e9387572998e5ecdac221950dab3e8c3b16af884"