Made version a substitution var.

example.yaml

@@ -6,6 +6,7 @@
 # --------------------------------------------------------------------------
 
 substitutions:
+  version: dev
   #name: bedside-lamp
   #friendly_name: Bedside Lamp
   #light_name: ${friendly_name} RGBWW Light
@@ -32,7 +33,7 @@ substitutions:
 packages:
   bslamp2:
     url: https://github.com/mmakaay/esphome-xiaomi_bslamp2
-    ref: dev
+    ref: ${version}
     files:
       - packages/core.yaml
       - packages/behavior_default.yaml

packages/core.yaml

@@ -4,6 +4,7 @@
 # --------------------------------------------------------------------------
 
 substitutions:
+  version: dev
   name: bedside-lamp
   friendly_name: Bedside Lamp
   light_name: ${friendly_name} RGBWW Light
@@ -28,7 +29,7 @@ esp32:
 
 # Retrieve the code for the xiaomi_bslamp2 platform from GitHub.
 external_components:
-  - source: github://mmakaay/esphome-xiaomi_bslamp2@dev
+  - source: github://mmakaay/esphome-xiaomi_bslamp2@${version}
     refresh: 60s
 
 # Disable the reboot timeout. By default, the lamp reboots after 15