chore(deps): update traefik docker tag to v2.8.4

Author: renovate[bot]

src/development/stack.yml

@@ -111,7 +111,7 @@ services:
       placement:
         constraints:
         - node.role == manager
-    image: traefik:v2.8.3@sha256:ad8c1935c4b901e10b62b6868d6369218793c69e7a7ea9c1d036fdc2b919e38e
+    image: traefik:v2.8.4@sha256:9717bde18a6e109c63a88e4b67725500c701768d7c044fc64c83efdb892b5738
     ports:
     - mode: host
       protocol: tcp