Add outputs variable published and publishedPackages (#26)

* Add outputs variable `published`

* publishedPackages

action.yml

@@ -7,6 +7,15 @@ inputs:
   publish:
     description: "The command to use to build and publish packages"
     required: false
+  version:
+    description: "The command to update version, edit CHANGELOG, read and delete changesets. Default to `changeset version` if not provided"
+    required: false
+outputs:
+  published:
+    description: A boolean value to indicate whether a publishing is happened or not
+  publishedPackages:
+    description: >
+      A JSON array to present the published packages. The format is `[{"name": "@xx/xx", "version": "1.2.0"}, {"name": "@xx/xy", "version": "0.8.9"}]`
 branding:
   icon: "package"
   color: "blue"