Fix up github workflows

[robbecker-wf]

Summary

Fix up Github Actions workflows by

• generate an SBOM
• auto publish on releases
• remove dart 2.18 and stable from matrix (will add back Dart 3 later)

[aviary2-wf]

Security Insights

No security relevant content was detected by automated scans.

Action Items

• Review PR for security impact; comment "security review required" if needed or unsure
• Verify aviary.yaml coverage of security relevant code

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[robbecker-wf]

QA+1 CI passes, SBOM attached. @Workiva/release-management-p

[rmconsole-wf]

+1 from RM