deps: bump langgraph-checkpoint from 2.1.1 to 3.0.1

Bumps [langgraph-checkpoint](https://github.com/langchain-ai/langgraph) from 2.1.1 to 3.0.1.
- [Release notes](https://github.com/langchain-ai/langgraph/releases)
- [Commits](langchain-ai/langgraph@checkpoint==2.1.1...checkpoint==3.0.1)

---
updated-dependencies:
- dependency-name: langgraph-checkpoint
  dependency-version: 3.0.1
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements.txt

@@ -60,7 +60,7 @@ langchain-oci==0.1.6
 langchain-oracledb==1.0.2
 langchain-text-splitters==0.3.11
 langgraph==0.6.7
-langgraph-checkpoint==2.1.1
+langgraph-checkpoint==3.0.1
 langgraph-prebuilt==0.6.4
 langgraph-sdk==0.2.6
 langsmith==0.4.27