[NonGNU ELPA] Dockerfile-Mode version 1.5

[ELPA update]

Version 1.5 of package Dockerfile-Mode has just been released in NonGNU ELPA.
You can now find it in M-x package-list RET.

Dockerfile-Mode describes itself as:
  Major mode for editing Docker's Dockerfiles

More at https://elpa.nongnu.org/nongnu/dockerfile-mode.html