add release job for mozilla amo

.gitlab-ci.yml

+variables:
+  NODE_TAG: 20
+
 stages:
   - build
   - release
 
 chrome_extension:
   stage: build
-  image: node:20
+  image: node:${NODE_TAG}
   rules:
     - if: $CI_COMMIT_TAG
   script:
@@ -16,7 +19,7 @@ chrome_extension:
 
 firefox_extension:
   stage: build
-  image: node:20
+  image: node:${NODE_TAG}
   rules:
     - if: $CI_COMMIT_TAG
   script:
@@ -48,3 +51,11 @@ release:
         - name: "firefox"
           filepath: /metager_search-firefox.zip
           url: "${CI_API_V4_URL}/projects/${CI_PROJECT_ID}/packages/generic/metager_search/${CI_COMMIT_TAG}/metager_search-${CI_COMMIT_TAG}-firefox.zip"
+
+amo:
+  stage: release
+  image: node:${NODE_TAG}
+  rules:
+    - if: $CI_COMMIT_TAG
+  script:
+    - npm run prod-ff-release