Update default version and add BASE_URL (#550)

public/v4/apps/changedetection.yml

@@ -2,6 +2,8 @@ captainVersion: 4
 services:
     $$cap_appname:
         image: dgtlmoon/changedetection.io:$$cap_version
+        environment:
+            BASE_URL: http://$$cap_appname.$$cap_root_domain
         volumes:
             - '$$cap_appname-data:/datastore'
         caproverExtra:
@@ -10,7 +12,7 @@ caproverOneClickApp:
     variables:
         - id: $$cap_version
           label: ChangeDetection.io version
-          defaultValue: 0.27
+          defaultValue: 0.39.3
           description: 'Check out their docker page for the valid tags https://hub.docker.com/r/dgtlmoon/changedetection.io/tags'
     instructions:
         start: >-