Bump coverlet.msbuild and Microsoft.NETFramework.ReferenceAssemblies (#979)

Author: dependabot[bot]

Directory.Packages.props

@@ -1,7 +1,7 @@
 <Project>
   <ItemGroup>
     <PackageVersion Include="BenchmarkDotNet" Version="0.14.0" />
-    <PackageVersion Include="coverlet.msbuild" Version="6.0.3" />
+    <PackageVersion Include="coverlet.msbuild" Version="6.0.4" />
     <PackageVersion Include="GitHubActionsTestLogger" Version="2.4.1" />
     <PackageVersion Include="MarkdownSnippets.MsBuild" Version="27.0.2" />
     <PackageVersion Include="MartinCostello.Logging.XUnit.v3" Version="0.5.1" />