add healthcheck (just checks for node) to Dockerfile and docker-compose.yml

docker-compose.yml

@@ -4,6 +4,10 @@ services:
     container_name: fgc # is printed in front of every output line
     image: ghcr.io/vogler/free-games-claimer # otherwise image name will be free-games-claimer-free-games-claimer
     build: .
+    healthcheck: # not that useful, but linter complained, see Dockerfile
+      test: "pgrep node"
+      interval: 10s
+      timeout: 5s
     ports:
       # - "5900:5900" # VNC server
       - "6080:6080" # noVNC (browser-based VNC client)