chore(deps): update dependency splat to v18

Author: renovate[bot]

src/Directory.Packages.props

@@ -9,7 +9,7 @@
     <PackageVersion Include="Nerdbank.GitVersioning" Version="3.9.50" />
     <PackageVersion Include="NuGet.Common" Version="6.14.0" />
     <PackageVersion Include="NuGet.Protocol" Version="6.14.0" />
-    <PackageVersion Include="Splat" Version="17.2.1" />
+    <PackageVersion Include="Splat" Version="18.1.1" />
     <PackageVersion Include="stylecop.analyzers" Version="1.2.0-beta.556" />
     <PackageVersion Include="Roslynator.Analyzers" Version="4.15.0" />
     <PackageVersion Include="ReactiveUI" Version="22.3.1" />