build(deps): update unstructured requirement from <0.12 to <0.15

Updates the requirements on [unstructured](https://github.com/Unstructured-IO/unstructured) to permit the latest version.
- [Release notes](https://github.com/Unstructured-IO/unstructured/releases)
- [Changelog](https://github.com/Unstructured-IO/unstructured/blob/main/CHANGELOG.md)
- [Commits](Unstructured-IO/unstructured@0.2.0...0.14.2)

---
updated-dependencies:
- dependency-name: unstructured
  dependency-type: direct:production
...

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

pyproject.toml

@@ -101,7 +101,7 @@ fileio = [
 nlp = [
   "aiohttp<3.10",
   "langchain",
-  "unstructured<0.12",
+  "unstructured<0.15",
 ]
 notebook = [
   "nbclient<0.11",