Added the scorecard github action and its badge

[harshitasao]

Fixes https://github.com/knative/community/issues/1592

Proposed Changes

PR to add the Scorecard GitHub Action and its badge in the README file.

Release Note

NONE

[knative-prow[bot]]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[knative-prow[bot]]

Welcome @harshitasao! It looks like this is your first PR to knative/serving 🎉

[knative-prow[bot]]

Hi @harshitasao. Thanks for your PR.

I'm waiting for a knative member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[harshitasao]

cc @davidhadas

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 84.46%. Comparing base (c51ee6c) to head (e17210f). Report is 44 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #15473 +/- ## ========================================== + Coverage 84.44% 84.46% +0.02% ========================================== Files 219 219 Lines 13608 13608 ========================================== + Hits 11491 11494 +3 + Misses 1744 1743 -1 + Partials 373 371 -2 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[skonto]

/ok-to-test

[skonto]

@davidhadas gentle ping

[davidhadas]

@harshitasao

I suggest we separate this PR into 2 parts:

First, lets add the Scorecard GitHub Action << I am ok with the suggested changed to .github (also, if you have a way to add a comment in the Scorecard indicating "this scorecard is under community evaluation" - please do so, can it be done by changing the scoreboard title?)

Then, lets resolve all pending issues with the Scorecard such as those indicated in https://github.com/knative/serving/issues/15474

Last, when the community is ok with the Scorecard, we can add the comment and badge to the community readme file.

I therefore suggest to remove the changes to the readme (and badge) from this PR and add it in a future PR when the Scorecard is community approved.