Problem: default cmd is wrong (#44)

Solution:
- set default cmd to None, resolve the correct one later

pystarport/cli.py

@@ -4,7 +4,7 @@
 
 import fire
 
-from .app import CHAIN, IMAGE, SUPERVISOR_CONFIG_FILE
+from .app import IMAGE, SUPERVISOR_CONFIG_FILE
 from .bot import BotCLI, BotClusterCLI
 from .cluster import ClusterCLI, init_cluster, start_cluster, start_tail_logs_thread
 from .cosmoscli import CosmosCLI
@@ -51,7 +51,7 @@ def serve(data, config, base_port, dotenv, cmd, quiet, no_remove=False):
 
 
 class CLI:
-    def __init__(self, /, cmd=CHAIN):
+    def __init__(self, /, cmd=None):
         """
         :param cmd: path to the chain binary
         """

pystarport/cluster.py

@@ -48,7 +48,7 @@ def __init__(
         self,
         data,
         chain_id="chainmaind",
-        cmd=CHAIN,
+        cmd=None,
         zemu_address=ZEMU_HOST,
         zemu_button_port=ZEMU_BUTTON_PORT,
     ):