Outsource the convoluted `web-ext sign` wrapping code (#2)

package.json

@@ -12,7 +12,7 @@
     "zip": "git archive -o build/lesspass.zip HEAD:extension && npm run zip:firefox && npm run zip:chrome && rm build/lesspass.zip",
     "build": "npm run clean && gulp && npm run zip",
     "release": "npm run build && npm run release-cws && npm run release-amo",
-    "release-amo": "cd extension && OK='has been submitted for review.' && web-ext sign | sed -n \"s/\\($OK\\).*$/\\1/;1,/$OK/p\" | perl -pe 'BEGIN { $s=1 } END { exit $s } $s=0 if /'\"$OK\"'/;'",
+    "release-amo": "cd extension && webext submit",
     "release-cws": "webstore upload --source build/lesspass.chrome-v$npm_package_version.zip --auto-publish",
     "dev": "cd extension && web-ext run",
     "test": "echo 'no test'"
@@ -24,7 +24,8 @@
     "chrome-webstore-upload-cli": "^1.1.1",
     "gulp": "^3.9.1",
     "json": "^9.0.6",
-    "web-ext": "^1.9.1"
+    "web-ext": "^1.9.1",
+    "webext": "1.9.1-with-submit.1"
   },
   "private": true
 }