chore(deps): update dependency polyfill to 9.20.0

[thomhurst]

This PR contains the following updates:

Package	Type	Update	Change
Polyfill	nuget	minor	9.18.0 → 9.20.0

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Release Notes

SimonCropp/Polyfill (Polyfill)

v9.20.0

Compare Source

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Configuration

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🚦 Automerge: Enabled.

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This PR has been generated by Renovate Bot.

[claude]

This is a routine automated dependency update from Renovate Bot, bumping the Polyfill package from 9.18.0 to 9.20.0 in Directory.Packages.props.

Summary of change: Single-line version bump in the centralized package version management file. No logic, no structural changes.

Assessment:

• The change is minimal and low-risk. Polyfill is a source-generator-based package, meaning it injects polyfill APIs at compile time rather than shipping runtime binary dependencies. A minor version bump (9.18 → 9.20) in a well-maintained package like this is unlikely to introduce breaking changes.
• The PR has auto-merge enabled, which is appropriate for this type of automated dependency update.
• The release notes link is sparse — it would be worth briefly checking the upstream changelog to confirm no new polyfills were added that might conflict with existing TUnit API surface, especially given TUnit's multi-target setup (net8.0;net9.0;net10.0). Since net10.0 is a target and Polyfill typically adds APIs that are only present in newer runtimes, newly added polyfills from v9.19/v9.20 could potentially shadow or conflict with native APIs on net10.0. This is generally handled gracefully by the package itself, but worth being aware of.
• No concerns about AOT compatibility or source generator output changes; Polyfill does not affect TUnit's own source generator snapshots.

No issues found. This update looks safe to merge.