Clean up duplicated heading in v0.3.6 release notes

[bernalde]

Context

The GitHub release for v0.3.6 was created successfully by TagBot, but the release body currently repeats the ## PySA v0.3.6 heading.

Release: https://github.com/JuliaQUBO/PySA.jl/releases/tag/v0.3.6

Scope

• Edit the v0.3.6 GitHub release body to remove the duplicated heading.
• Keep the diff link, bullet list, merged PRs, and closed issues intact.
• No package code changes are needed.

Acceptance criteria

• The v0.3.6 release page has a single clear heading for the release notes.
• The release still includes the diff link and generated TagBot summary.

[bernalde]

Resolved directly on the v0.3.6 GitHub release page by removing the duplicated release heading while preserving the diff link and generated TagBot summary. No package code changes were needed.