update cosign signing config to support cosign v3

[amirejaz]

This PR updates the GoReleaser signing configuration to be compatible with cosign v3.

Why

Cosign v3 requires the --bundle flag when using --output-signature or keyless signing. Without it, the release workflow fails with:

[Copilot]

Pull Request Overview

Updates GoReleaser configuration to ensure compatibility with cosign v3 by adding the required --bundle flag to the signing configuration. This prevents release workflow failures that occur when using cosign v3 without proper bundle configuration.

• Added --bundle=${signature} flag to cosign signing arguments for v3 compatibility

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 53.38%. Comparing base (012d3b8) to head (a38e91f).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2246      +/-   ##
==========================================
+ Coverage   53.32%   53.38%   +0.05%     
==========================================
  Files         231      231              
  Lines       29529    29529              
==========================================
+ Hits        15747    15764      +17     
+ Misses      12649    12628      -21     
- Partials     1133     1137       +4     

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