Remove mentions of MAIN_DOMAIN (#263)

This was only used in the multiplayer service and WEBSOCKET_ALLOWED_ORIGIN has since been introduced as the preferred environment variable

Author: BriBread

charts/retool/values.yaml

@@ -499,7 +499,7 @@ multiplayer:
 
   # Set environment variables for multiplayer pods, e.g. defining which origin to use
   # environmentVariables:
-  #   MAIN_DOMAIN: "retool.foo.com"
+  #   WEBSOCKET_ALLOWED_ORIGIN: "retool.foo.com"
 
   # Annotations for multiplayer pods
   annotations: {}

values.yaml

@@ -499,7 +499,7 @@ multiplayer:
 
   # Set environment variables for multiplayer pods, e.g. defining which origin to use
   # environmentVariables:
-  #   MAIN_DOMAIN: "retool.foo.com"
+  #   WEBSOCKET_ALLOWED_ORIGIN: "retool.foo.com"
 
   # Annotations for multiplayer pods
   annotations: {}