chore: add example for updating all container images in set command

[EnriqueTejeda]

I recently needed to update all container images within a rollout but couldn't find a clear example in the documentation. Using * with the set command is a powerful way to achieve this efficiently (pkg/kubectl-argo-rollouts/cmd/set/set_image.go) .

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 with a list of types and scopes found here, (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.

[github-actions]

Go Published Test Results

2 164 tests   2 164 ✅  2m 54s ⏱️
  119 suites      0 💤
    1 files        0 ❌

Results for commit 90d9317.

♻️ This comment has been updated with latest results.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.27%. Comparing base (4f1edbe) to head (90d9317).
Report is 85 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3667   +/-   ##
=======================================
  Coverage   80.27%   80.27%           
=======================================
  Files         156      156           
  Lines       17964    17965    +1     
=======================================
+ Hits        14420    14421    +1     
  Misses       2631     2631           
  Partials      913      913           

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[github-actions]

E2E Tests Published Test Results

  4 files    4 suites   3h 26m 52s ⏱️
111 tests 100 ✅  6 💤  5 ❌
462 runs  423 ✅ 24 💤 15 ❌

For more details on these failures, see this check.

Results for commit 90d9317.

♻️ This comment has been updated with latest results.