Update pymongo requirement from <4.15,>=4.12 to >=4.12,<4.16 in /libs/langgraph-checkpoint-mongodb (#206)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Steven Silvester <steve.silvester@mongodb.com>

Author: dependabot[bot]

libs/langgraph-checkpoint-mongodb/pyproject.toml

@@ -11,7 +11,7 @@ requires-python = ">=3.9"
 dependencies = [
     "langgraph-checkpoint>=2.0.23,<3.0.0",
     "langchain-mongodb>=0.6.1",
-    "pymongo>=4.12,<4.15",
+    "pymongo>=4.12,<4.16",
 ]
 
 [dependency-groups]