Only update timeline when Spring Boot 4.x changes

[rujche]

Summary

• update workflow timeline logic to append a new timeline item only when Spring Boot 4.x entries change
• skip timeline update when only Spring Boot 3.x entries change
• keep timeline content limited to supported Spring Boot 4.x matrix entries

Why

• avoid noisy timeline updates for 3.x-only changes
• align timeline updates with the intended 4.x update signal

Validation

• Created PR before current PR: Update Spring Boot and Spring Cloud versions for the Spring compatibility tests azure-sdk-for-java#49640
• Created PR after current PR: TODO.

[Copilot]

Pull request overview

Updates the GitHub Actions workflow responsible for updating the Spring Cloud Azure support metadata PR so that timeline entries are only appended when Spring Boot 4.x support metadata changes, reducing timeline noise from 3.x-only updates.

Changes:

• Add Spring Boot 4.x-only diff detection to skip timeline updates when 4.x entries are unchanged.
• Restrict timeline content generation to SUPPORTED Spring Boot 4.x entries.
• Introduce a reusable SUPPORT_FILE variable for the support JSON path.

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[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

[rujche]

Superseded by #53