feat: --output for oras manifest index update

[wangxiaoxuan273]

What this PR does / why we need it:

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
part of #1053

Please check the following list:

• Does the affected code have corresponding tests, e.g. unit test, E2E test?
• Does this change require a documentation update?
• Does this introduce breaking changes that would require an announcement or bumping the major version?
• Do all new files have an appropriate license header?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.01%. Comparing base (071f060) to head (afda80b).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1502   +/-   ##
=======================================
  Coverage   86.00%   86.01%           
=======================================
  Files         117      117           
  Lines        4210     4226   +16     
=======================================
+ Hits         3621     3635   +14     
- Misses        351      353    +2     
  Partials      238      238           

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[qweeah]

Please make sure --output - make other stdout output silent. See #1503. Doesn't necessarily need to be done in this PR.

[wangxiaoxuan273]

Please make sure --output - make other stdout output silent. See #1503. Doesn't necessarily need to be done in this PR.

I'd like to do it in a future PR.

[shizhMSFT]

LGTM