Fix maturityLevel of loki, metrics-server, and vault

General MR

Summary

The following packages live under projects/graduated but did not update their maturityLevel to graduated.

• loki
• metrics-server
• vault

Relevant logs/screenshots

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Linked Issue

issue

Upgrade Notices

(Include any relevant notes about upgrades here or write "N/A" if there are none)

assigned to @bjacksonfv

approved this merge request

lgtm

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