Bump coverlet.msbuild from 6.0.3 to 6.0.4 in /src (#196)

Bumps [coverlet.msbuild](https://github.com/coverlet-coverage/coverlet) from 6.0.3 to 6.0.4.
- [Release notes](https://github.com/coverlet-coverage/coverlet/releases)
- [Commits](coverlet-coverage/coverlet@v6.0.3...v6.0.4)

---
updated-dependencies:
- dependency-name: coverlet.msbuild
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

src/GraphQL.IntrospectionModel.Tests/GraphQL.IntrospectionModel.Tests.csproj

@@ -17,7 +17,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="coverlet.msbuild" Version="6.0.3">
+    <PackageReference Include="coverlet.msbuild" Version="6.0.4">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>