feat(archive): allow specifying a compression level

[adamglt]

Allows setting a compression level for an archive's TarStrategy.
Default falls back to gzip.DefaultCompression, which is the current behavior.

Closes #2574 which contains more info.

[CLAassistant]

All committers have signed the CLA.

[adamglt]

Seems like a flaky test - rerun?

[simster7]

Looks good so far. Could you add some tests and add this to the appropriate example in examples/?

Also, if you could add this to the docs somewhere that would be great. I know the docs are lacking at the moment, so it might be hard to find a good place to add this. If so, feel free to create a file and I'll add it to the appropriate place during the refactor.

[adamglt]

Not really sure where to add tests - couldn't find anything testing the exported archive (it seems functional tests run on the examples?).

Added to the archive example and some in the README.md.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@3d14614). Click here to learn what that means.
The diff coverage is 10.25%.

@@            Coverage Diff            @@
##             master    #2575   +/-   ##
=========================================
  Coverage          ?   11.17%           
=========================================
  Files             ?       83           
  Lines             ?    32632           
  Branches          ?        0           
=========================================
  Hits              ?     3647           
  Misses            ?    28487           
  Partials          ?      498

Impacted Files	Coverage Δ
pkg/apis/workflow/v1alpha1/workflow_types.go	10.93% <ø> (ø)
...kg/apis/workflow/v1alpha1/zz_generated.deepcopy.go	0% <0%> (ø)
pkg/apis/workflow/v1alpha1/generated.pb.go	0.46% <0%> (ø)
workflow/executor/executor.go	4.41% <0%> (ø)
util/archive/archive.go	62.19% <100%> (ø)

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[simster7]

Much better now. Left a suggestion for a test

[simster7]

Excellent, great contribution! Can I encourage you to do more? 🙂

[adamglt]

@simster7 is this planned for 2.7.4 or 2.8.x?

[simster7]

@simster7 is this planned for 2.7.4 or 2.8.x?

This is planned for 2.8 at the end of this month

[simster7]

@adamglt There should also be a 2.8-rc1 release in a week or so

[simster7]

@adamglt v2.8.0-rc1 has been released with this