fix(release): Use correct cargo release manifest key name

[teor2345]

Motivation

I used the wrong name for the cargo release version replacements table.

This makes cargo log an "unused manifest key: metadata" warning.

Specifications

The correct table name is package.metadata:
https://doc.rust-lang.org/cargo/reference/manifest.html#the-metadata-table

Testing

The warning disappears after this fix.

Review

This is a release blocker, but the other release blockers will take much longer to implement and merge.

Reviewer Checklist

• Are the PR labels correct?
• Does the code do what the ticket and PR says?
  • Does it change concurrent code, unsafe code, or consensus rules?
• How do you know it works? Does it have tests?

[arya2]

Thank you.

[codecov]

Codecov Report

Merging #7028 (f174b85) into main (56a7638) will decrease coverage by 0.10%.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7028      +/-   ##
==========================================
- Coverage   77.47%   77.38%   -0.10%     
==========================================
  Files         310      310              
  Lines       41647    41647              
==========================================
- Hits        32268    32228      -40     
- Misses       9379     9419      +40     

[teor2345]

Failed due to #7015, but with the error "Failed to establish a new connection: [Errno 101] Network is unreachable":
https://github.com/ZcashFoundation/zebra/actions/runs/5328639930/jobs/9654625362?pr=7028#step:12:95