chore(security): add .grype.yaml to ignore negeligible vulnerabilities

[outsinre]

Summary

Our release GHA workflow scans generated Docker images and reports vulnerabilities.

Some of the vulnerabilities are negligible and some won't be fixed by upstream. This PR adds a Grype configuration to ignore those vulnerabilities.

According to https://github.com/anchore/grype#configuration and https://github.com/marketplace/actions/anchore-container-scan#additional-configuration, we put the .grype.yaml in the root of the repo.

Checklist

• [n/a] The Pull Request has tests
• [n/a] There's an entry in the CHANGELOG
• [n/a] There is a user-facing docs PR against https://github.com/Kong/docs.konghq.com - PUT DOCS PR HERE

Full changelog

• add .grype.yaml to ignore negligible and won't-fix vulnerabilities

Issue reference

Fix #FTI-5195

[VicYP]

@kikito FYI. Thanks.

[outsinre]

2.8.4.3-rc1 still reports the vulnerability: https://github.com/Kong/kong-ee/actions/runs/6081756831

[outsinre]

Close due to no authority decision.

[Dolat2057]

Testing the pull request