build: bump version to v0.21.3

[ziggie1984]

Bumps the version from 0.21.3-beta.rc1 to 0.21.3-beta, dropping the release candidate suffix for the final v0.21.3 release.

This mirrors the previous release-candidate → final transitions done for v0.21.2 (#11063) and v0.20.4 (#11153).

[github-actions]

🟡 PR Severity: MEDIUM

gh pr view | 1 files | 2 lines changed

🟡 Medium (1 files)

• build/version.go - uncategorized Go file (version string bump, not part of any critical/high package)

Analysis

This PR only touches build/version.go, changing the version string from 0.21.3-beta.rc1 to 0.21.3-beta to drop the release-candidate suffix ahead of the final v0.21.3 release. It's a single-line, mechanical version bump with no logic changes, mirroring prior release-candidate → final transitions (#‌11063, #‌11153). build/* isn't in the critical/high package lists, so it falls to the default "other Go files" tier. No file-count or line-count bump thresholds are met.

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[Roasbeef]

LGTM