Allow to install modules from just one cpanfile.snapshot

[KES777]

It seems if we have on production server just cpanfile.snapshot that is enough to install modules, but actually not =( cpanfile is requred too:

#12 [8/9] RUN  cpm install -w 16 --no-test -L ./local --snapshot cpanfile.snapshot
#12 2.540 Need arguments or cpm.yml/cpanfile
#12 ERROR: executor failed running [/bin/bash -c cpm install -w 16 --no-test -L ./local --snapshot cpanfile.snapshot]: exit code: 2

Why it is not possible to install without cpanfile?

[skaji]

cpanfile specifies what modules to be installed.
cpanfile.snapshot specifies where modules exist (in other words, cpm uses cpanfiles.snapshot for a resolver).

So I don't have plan to install modules only with cpanfile.snapshot in the near future.