chore(deps): update emqx/emqx docker tag to v5.8.1 (#2295)

* chore(deps): update emqx/emqx docker tag to v5.8.1

* Update app version [skip ci]

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Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: github-action update-app-version <githubaction@githubaction.com>

apps/emqx/5.8.1/docker-compose.yml

@@ -1,6 +1,6 @@
 services:
   emqx:
-    image: emqx/emqx:5.8.0
+    image: emqx/emqx:5.8.1
     container_name: ${CONTAINER_NAME}
     restart: always
     networks: