update command: csst --version

app/csst.py

@@ -16,6 +16,10 @@ assert os.path.exists(DOT_CSST), f"`{DOT_CSST}` does not exist!"
 
 # Create main command group 'csst'
 @click.group()
+@click.version_option(
+    version=os.environ.get("BUILD", "BUILD not found"),
+    prog_name="CSST Pipeline Operation Tool",
+)
 def csst():
     """CSST Pipeline Operation Tool"""
     pass