feat: Add application/tag+zip OCI media type for compatibility

[danielfbm]

Adds a constant for tar.gzip mediaType. Used for helm oci chart storage on helm 3.6 and prior

Changes

• Adds a constant for tar.gzip mediaType. Used for helm oci chart storage on helm 3.6 and prior

Submitter Checklist

As the author of this PR, please check off the items in this checklist:

• spec PR link included
• Follows the commit message standard
• Meets the contributing guidelines (including
  functionality, content, code)
• Test cases with documentation and functionality works as expected using current and related github repos (MUST deploy and check)
• Release notes block below has been filled in or deleted (only if no user facing changes)

Release Notes

[alaudabot]

Quality Gate

_{updated at Fri Jan 6 14:03:09 UTC 2023}

Status: OK 🟢

Metric	Rating
🐛 Bugs: 0	🏗 Reliability: A 🟢
🤮 Code smells: 0	🛠 Maintainability: A 🟢
⚠️ Vulnerabilities: 0	🦺 Security: A 🟢
🔥 Security hotspots: 0	🔎 Security Review: A 🟢

Metric	Change set	Target (main)	After
🧪 Code coverage	0.00% Coverage on 0 new lines	51.90%	51.90% ↔️ 🟢 estimated after merge allowed difference 0
👥 Duplications	0.00% Duplications on 0 new lines	3.30%	3.30% ↔️ 🟢 estimated after merge allowed difference 0

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