build(deps): bump coverlet.msbuild from 3.0.3 to 3.1.0 in /src (#309)

Bumps [coverlet.msbuild](https://github.com/coverlet-coverage/coverlet) from 3.0.3 to 3.1.0.
- [Release notes](https://github.com/coverlet-coverage/coverlet/releases)
- [Commits](https://github.com/coverlet-coverage/coverlet/commits/v3.1.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

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

src/ReactiveUI.Validation.Tests/ReactiveUI.Validation.Tests.csproj

@@ -19,7 +19,7 @@
     <PackageReference Include="PublicApiGenerator" Version="10.2.0" />
     <PackageReference Include="xunit.runner.console" Version="2.4.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3" />
-    <PackageReference Include="coverlet.msbuild" Version="3.0.3">
+    <PackageReference Include="coverlet.msbuild" Version="3.1.0">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
     </PackageReference>