Use reusuable release workflow in sigstore/sigstore

[k4leung4]

Signed-off-by: Kenny Leung kleung@chainguard.dev

Summary

Leverage the reusable Release workflow in sigstore/sigstore repo so releases will be cut in the same manner across Cosign|Rekor|Fulcio.

The reusable workflow is pending review in sigstore/sigstore#325

Before this workflow works, the included shell script needs to be executed to setup necessary workflow identity provider that grants the needed permissions to build and push the release.

Ticket Link

Fixes

Works toward fixing https://github.com/sigstore/public-good-instance/issues/50

Release Note

[codecov-commenter]

Codecov Report

Merging #1599 (b65ab08) into main (3eadb75) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #1599   +/-   ##
=======================================
  Coverage   27.90%   27.90%           
=======================================
  Files         137      137           
  Lines        7783     7783           
=======================================
  Hits         2172     2172           
  Misses       5383     5383           
  Partials      228      228           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3eadb75...b65ab08. Read the comment docs.