chore: bump version to 2.68.0 [skip ci]

Author: github-actions[bot]

CHANGELOG.md

@@ -1,3 +1,13 @@
+## [v2.68.0](https://github.com/docling-project/docling-core/releases/tag/v2.68.0) - 2026-03-07
+
+### Feature
+
+* Add plain-text serializer ([#522](https://github.com/docling-project/docling-core/issues/522)) ([`e363c95`](https://github.com/docling-project/docling-core/commit/e363c951d8b67b67a23e7bd4a7d92969a7875a33))
+
+### Fix
+
+* Prevent infinite loop in LineBasedTokenChunker with unbreakable tokens ([#533](https://github.com/docling-project/docling-core/issues/533)) ([`a661bb1`](https://github.com/docling-project/docling-core/commit/a661bb10cb46a7b8ce338773e6e95e558b96d669))
+
 ## [v2.67.1](https://github.com/docling-project/docling-core/releases/tag/v2.67.1) - 2026-03-05
 
 ### Fix

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "docling-core"
-version = "2.67.1"  # DO NOT EDIT, updated automatically
+version = "2.68.0"  # DO NOT EDIT, updated automatically
 description = "A python library to define and validate data types in Docling."
 license = "MIT"
 license-files = ["LICENSE"]