Bump coverlet.collector in /tests/NHapi.NUnit.SourceGeneration

Bumps [coverlet.collector](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.collector
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

tests/NHapi.NUnit.SourceGeneration/NHapi.NUnit.SourceGeneration.csproj

@@ -13,7 +13,7 @@
     <PackageReference Include="NUnit" Version="3.13.2" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.0.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.10.0" />
-    <PackageReference Include="coverlet.collector" Version="3.0.3">
+    <PackageReference Include="coverlet.collector" Version="3.1.0">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>