bug: ENTRYPOINT is added without correct structure to the Containerfile

[kbdharun]

The ENTRYPOINT command in the resulting Containerfile (from Vib's recipe having something like entrypoint: ["/app"]) has this format ENTRYPOINT /app instead of Docker's normal ENTRYPOINT ["/app"] format; since ours isn't enclosed in the correct format Docker defaults the final path/command to /bin/sh -c /app.

Ref. https://github.com/Vanilla-OS/Vib/blob/main/api/structs.go and https://docs.docker.com/reference/dockerfile/#cmd