feat: provide shell completion. Closes #619

[kostis-codefresh]

Signed-off-by: Kostis Kapelonis [email protected]

Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this is a chore.
• The title of the PR is (a) conventional, (b) states what changed, and (c) suffixes the related issues number. E.g. "fix(controller): Updates such and such. Fixes #1234".
• I've signed my commits with DCO
• I have written unit and/or e2e tests for my change. PRs without these are unlikely to be merged.
• My builds are green. Try syncing with master if they are not.
• My organization is added to USERS.md.

[codecov]

Codecov Report

Merging #1478 (6fc88cb) into master (ba9af78) will increase coverage by 0.07%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1478      +/-   ##
==========================================
+ Coverage   81.35%   81.43%   +0.07%     
==========================================
  Files         108      109       +1     
  Lines       14505    14564      +59     
==========================================
+ Hits        11801    11860      +59     
  Misses       2089     2089              
  Partials      615      615              

Impacted Files	Coverage Δ
pkg/kubectl-argo-rollouts/cmd/cmd.go	100.00% <100.00%> (ø)
...kubectl-argo-rollouts/cmd/completion/completion.go	100.00% <100.00%> (ø)

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[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
35.3% Duplication

[alexmt]

LGTM! Retrying e2e tests and merging once it is green.