fix broken (*compose.DockerCompose).Copy method

[fabriciojs]

Issue	-
🪲 Bug Fix	Yes
⚠️ Break Change	Yes/No

Description

Recently introduced builder.Command.Copy() was making compose.DockerCompose to be lost within shell.Interactive, which would cause for not found command errors.

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Notes

The test here tackles only the Copy itself. I plan on writing some end-to-end test so we can catch stuff like this before in our workflow.

[codecov]

Codecov Report

Merging #271 (bfea26e) into master (510952b) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #271   +/-   ##
=======================================
  Coverage   88.47%   88.47%           
=======================================
  Files          67       67           
  Lines        2629     2630    +1     
=======================================
+ Hits         2326     2327    +1     
  Misses        281      281           
  Partials       22       22           

Impacted Files	Coverage Δ
cmd/compose/docker-compose.go	100.00% <100.00%> (ø)

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