Update document for add reviewer

[ttakahashi21]

Enhancement Description

• One-line enhancement description (can be used as a release note): Update document for add reviewer
• Kubernetes Enhancement Proposal: Update document for add reviewer and approvers #3630
• Discussion Link: KEP-3294: Add proposal for provisioning volumes from cross-namespace snapshots #3295 (comment)
• Primary contact (assignee): @ttakahashi21
• Responsible SIGs: @kubernetes/sig-storage-feature-requests
• Enhancement target (which target equals to which milestone):
  • Alpha release target (x.y): 1.26
  • Beta release target (x.y):
  • Stable release target (x.y):
• Alpha
  • KEP (k/enhancements) update PR(s):
  • Code (k/k) update PR(s):
  • Docs (k/website) update PR(s):

Please keep this description up to date. This will help the Enhancement Team to track the evolution of the enhancement efficiently.

[k8s-ci-robot]

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