fix: wrong act runner config

gitea/compose.yml

@@ -81,11 +81,6 @@ services:
     restart: always
     networks:
       - compose_network
-      # Job containers join Docker's real "bridge" network (see
-      # runner-config.yaml's container.network) - this container needs to be
-      # on it too so its auto-detected cache-server address is one they can
-      # actually reach.
-      - default_bridge
   db:
     image: postgres:16-alpine
     container_name: gitea_db
@@ -107,6 +102,3 @@ networks:
   compose_network:
     name: ${NETWORK_NAME}
     external: true
-  default_bridge:
-    name: bridge
-    external: true