Adds version CLI command (#12619)

Will be automatically bumped with `poetry version patch`.

@efriis @hwchase17

---------

Co-authored-by: Erick Friis <erick@langchain.dev>

libs/cli/langchain_cli/cli.py

@@ -6,6 +6,8 @@ from typing_extensions import Annotated
 from langchain_cli.namespaces import app as app_namespace
 from langchain_cli.namespaces import template as template_namespace
 
+__version__ = "0.0.11"
+
 app = typer.Typer(no_args_is_help=True, add_completion=False)
 app.add_typer(
     template_namespace.package_cli, name="template", help=template_namespace.__doc__
@@ -13,6 +15,26 @@ app.add_typer(
 app.add_typer(app_namespace.app_cli, name="app", help=app_namespace.__doc__)
 
 
+def version_callback(show_version: bool) -> None:
+    if show_version:
+        typer.echo(f"langchain-cli {__version__}")
+        raise typer.Exit()
+
+
+@app.callback()
+def main(
+    version: bool = typer.Option(
+        False,
+        "--version",
+        "-v",
+        help="Print the current CLI version.",
+        callback=version_callback,
+        is_eager=True,
+    ),
+):
+    pass
+
+
 @app.command()
 def serve(
     *,