Upgrade NuGet packages to address vulnerabilities

Author: paulirwin

test/F23.StringSimilarity.Tests/F23.StringSimilarity.Tests.csproj

@@ -18,9 +18,9 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.1.0" />
-    <PackageReference Include="xunit" Version="2.4.1" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3">
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
+    <PackageReference Include="xunit" Version="2.9.3" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
     </PackageReference>