Bump coverlet.collector from 3.1.1 to 3.1.2 in /src (#210)

Bumps [coverlet.collector](https://github.com/coverlet-coverage/coverlet) from 3.1.1 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.collector
  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/AzureIoTHub.Portal.Server.Tests/AzureIoTHub.Portal.Server.Tests.csproj

@@ -12,7 +12,7 @@
     <PackageReference Include="Moq" Version="4.16.1" />
     <PackageReference Include="NUnit" Version="3.13.2" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.2.1" />
-    <PackageReference Include="coverlet.collector" Version="3.1.1">
+    <PackageReference Include="coverlet.collector" Version="3.1.2">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>