chore(deps): update dependency tunit.core to 1.5.6 (#900)

Signed-off-by: Martin Stühmer <me@samtrion.net>
Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Martin Stühmer <me@samtrion.net>

Author: renovate[bot]

Directory.Packages.props

@@ -26,7 +26,7 @@
     <PackageVersion Include="Polyfill" Version="9.3.1" />
     <PackageVersion Include="PublicApiGenerator" Version="11.5.4" />
     <PackageVersion Include="TUnit" Version="1.5.6" />
-    <PackageVersion Include="TUnit.Core" Version="1.5.1" />
+    <PackageVersion Include="TUnit.Core" Version="1.5.6" />
     <PackageVersion Include="Verify.MSTest" Version="31.8.0" />
     <PackageVersion Include="Verify.NUnit" Version="31.8.0" />
     <PackageVersion Include="Verify.TUnit" Version="31.8.0" />