CI: Release snap from CI

.gitlab-ci.yml

@@ -225,6 +225,12 @@ update-dependencies:
     - export RELEASE_VERSION=$(echo $CI_COMMIT_TAG | grep -oE "\d+\.\d+\.\d+")
     - export PACKAGE_REGISTRY_URL="${CI_API_V4_URL}/projects/${CI_PROJECT_ID}/packages/generic/fluffychat/${RELEASE_VERSION}"
 
+snap_stable:
+  extends: .release
+  image: cibuilds/snapcraft:core18
+  script: [./scripts/publish-snap-stable.sh]
+  needs: [build_linux_x86]
+
 upload-android:
   extends: .release
   script: