Bundle in-tree extensions as npm/tgz (#2807)

Signed-off-by: Jari Kolehmainen <jari.kolehmainen@gmail.com>

package.json

@@ -98,8 +98,8 @@
         "from": "extensions/",
         "to": "./extensions/",
         "filter": [
-          "**/*.js*",
-          "**/*.yml*",
+          "**/*.tgz",
+          "**/package.json",
           "!**/node_modules"
         ]
       },