fix(ci): remove excessive SHA tag from Docker image releases

[AbdelrhmanHamouda]

Summary

Remove the full commit SHA tag from the release workflow's Docker image tagging strategy to eliminate registry pollution while maintaining full traceability.

Changes

• Remove ,${{ github.sha }} from ko build tags parameter in .github/workflows/release.yaml
• Future releases will only create two tags: version tag (e.g., v2.0.0) and latest

Rationale

The SHA tag was introduced in commit c68b6311 (Jan 20, 2026) during the Go operator CI/CD rewrite. While SHA tags can provide traceability, they create unnecessary registry pollution because:

1. Version tags already provide full traceability - Git tags are immutable and point to specific commits
2. Docker images have SHA256 digests - For absolute immutability needs, use image digests
3. Users prefer semantic versions - For rollbacks and deployments, version tags are more practical
4. SHA tags clutter DockerHub - 40-character tags accumulate without adding practical value

Impact

• Risk Level: LOW
• Single-line removal (not modification)
• No downstream dependencies on SHA tags
• Easy rollback if needed
• Only affects future releases (existing images unchanged)
• Multi-platform build functionality unaffected

Verification Plan

After merge, verify with next release:

• Build completes successfully
• Multi-platform images created (linux/amd64, linux/arm64)
• Only version + latest tags appear on DockerHub
• No SHA-based tag created
• Image pull works: docker pull lotest/locust-k8s-operator:<version-tag>

Optional Follow-up

Consider cleaning up existing SHA-based tags from DockerHub manually or via API to reduce clutter.

[codacy-production]

Coverage summary from Codacy

See diff coverage on Codacy

Coverage variation	Diff coverage
✅ -0.28%	✅ ∅

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (419c011)	2118	1804	85.17%
Head commit (65a1afb)	2118 (+0)	1798 (-6)	84.89% (-0.28%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#278)	0	0	∅ (not applicable)

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

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