Add ctx everywhere

[jonjohnsonjr]

I noticed that hitting ctrl-C didn't work when pushing images, this should fix that.

[codecov-io]

Codecov Report

Merging #268 (7b3d17c) into master (960e6a3) will not change coverage.
The diff coverage is 80.00%.

@@           Coverage Diff           @@
##           master     #268   +/-   ##
=======================================
  Coverage   36.89%   36.89%           
=======================================
  Files          33       33           
  Lines        1461     1461           
=======================================
  Hits          539      539           
  Misses        833      833           
  Partials       89       89           

Impacted Files	Coverage Δ
pkg/commands/publisher.go	0.00% <0.00%> (ø)
pkg/commands/resolver.go	12.42% <ø> (ø)
pkg/internal/testing/fixed.go	69.56% <ø> (ø)
pkg/publish/daemon.go	32.00% <ø> (ø)
pkg/publish/kind.go	0.00% <ø> (ø)
pkg/publish/layout.go	44.11% <ø> (ø)
pkg/publish/tarball.go	63.88% <ø> (ø)
pkg/publish/default.go	63.49% <100.00%> (ø)
pkg/publish/multi.go	60.00% <100.00%> (ø)
pkg/publish/shared.go	93.75% <100.00%> (ø)
... and 1 more

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