add version to cli

llama_stack/cli/stack/stack.py

@@ -5,6 +5,7 @@
 # the root directory of this source tree.
 
 import argparse
+from importlib.metadata import version
 
 from llama_stack.cli.subcommand import Subcommand
 
@@ -24,6 +25,12 @@ class StackParser(Subcommand):
             description="Operations for the Llama Stack / Distributions",
         )
 
+        self.parser.add_argument(
+            "--version",
+            action="version",
+            version=f"llama-stack {version('llama-stack')}",
+        )
+
         subparsers = self.parser.add_subparsers(title="stack_subcommands")
 
         # Add sub-commands