fix(markdown): expand marked version range to support marked v18 (#5060)

@platejs/markdown pinned marked to ^15.0.12, causing applications using marked v18
to ship duplicate versions of marked in their bundle and lockfile.

Fix:
- Expand marked dependency version specifier in package.json to ^15.0.12 || ^16.0.0 || ^17.0.0 || ^18.0.0.
- Add patch changeset for @platejs/markdown.

Closes #5060

Author: SamarthNimangre

.changeset/fix-markdown-marked-v18-version-range.md

@@ -0,0 +1,5 @@
+---
+"@platejs/markdown": patch
+---
+
+Expand `marked` dependency version range in `@platejs/markdown` to allow `marked` v15 through v18 (`^15.0.12 || ^16.0.0 || ^17.0.0 || ^18.0.0`), eliminating duplicate lockfile entries for projects using `marked` v18.

packages/markdown/package.json

@@ -44,7 +44,7 @@
   "dependencies": {
     "@platejs/date": "workspace:*",
     "lodash": "^4.17.23",
-    "marked": "^15.0.12",
+    "marked": "^15.0.12 || ^16.0.0 || ^17.0.0 || ^18.0.0",
     "mdast-util-math": "3.0.0",
     "mdast-util-mdx": "3.0.0",
     "react-compiler-runtime": "^1.0.0",