chore(deps): update dependency xunit.analyzers to 1.20.0

Author: renovate[bot]

src/directory.packages.props

@@ -26,7 +26,7 @@
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageVersion Include="Microsoft.Reactive.Testing" Version="6.0.1" />
     <PackageVersion Include="xunit" Version="2.9.3" />
-    <PackageVersion Include="xunit.analyzers" Version="1.19.0" />
+    <PackageVersion Include="xunit.analyzers" Version="1.20.0" />
     <PackageVersion Include="xunit.runner.visualstudio" Version="2.8.2" />
   </ItemGroup>