chore(deps): update tunit to 1.21.6

[thomhurst]

This PR contains the following updates:

Package	Type	Update	Change
TUnit	nuget	patch	1.21.0 → 1.21.6
TUnit.AspNetCore	nuget	patch	1.21.0 → 1.21.6
TUnit.Assertions	nuget	patch	1.21.0 → 1.21.6
TUnit.Assertions.FSharp	nuget	patch	1.21.0 → 1.21.6
TUnit.Core	nuget	patch	1.21.0 → 1.21.6
TUnit.Engine	nuget	patch	1.21.0 → 1.21.6
TUnit.Playwright	nuget	patch	1.21.0 → 1.21.6

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Release Notes

thomhurst/TUnit (TUnit)

v1.21.6: 1.21.6

What's Changed

Other Changes

• perf: replace object locks with Lock type for efficient synchronization by @​thomhurst in #​5219
• perf: parallelize test metadata collection for source-generated tests by @​thomhurst in #​5221
• perf: use GetOrAdd args overload to eliminate closure allocations in event receivers by @​thomhurst in #​5222
• perf: self-contained TestEntry with consolidated switch invokers eliminates per-test JIT by @​thomhurst in #​5223

Dependencies

• chore(deps): update tunit to 1.21.0 by @​thomhurst in #​5220

Full Changelog: v1.21.0...v1.21.6

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This PR has been generated by Renovate Bot.

[claude]

Code Review

This is a routine dependency bump updating all TUnit packages from 1.21.0 to 1.21.6 across Directory.Packages.props and the template project files.

Summary of changes included in 1.21.6

Per the release notes, this patch includes several performance improvements:

• #5219: Replace object locks with the new Lock type for more efficient synchronization
• #5221: Parallelise test metadata collection for source-generated tests
• #5222: Use GetOrAdd args overload to eliminate closure allocations in event receivers
• #5223: Self-contained TestEntry<T> with consolidated switch invokers to reduce per-test JIT overhead

Review

The changes are purely mechanical version bumps — all 7 packages are updated consistently to the same version (1.21.6), with no version skew. Central package management (Directory.Packages.props) is updated alongside the template project files that pin versions directly (which is expected since templates are standalone and don't inherit the central props).

No concerns. The PR is straightforward and correct. Auto-merge is appropriately enabled.