Bump coverlet.msbuild from 2.9.0 to 3.1.2

Bumps [coverlet.msbuild](https://github.com/coverlet-coverage/coverlet) from 2.9.0 to 3.1.2.
- [Release notes](https://github.com/coverlet-coverage/coverlet/releases)
- [Commits](https://github.com/coverlet-coverage/coverlet/commits)

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

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

Author: dependabot[bot]

test/json-ld.net.tests/json-ld.net.tests.csproj

@@ -21,7 +21,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="coverlet.msbuild" Version="2.9.0" />
+    <PackageReference Include="coverlet.msbuild" Version="3.1.2" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.7.1" />
     <PackageReference Include="xunit" Version="2.4.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3" />