Increase code coverage

[sungam3r]

This repo was configured to support upload code coverage info to CodeCov services - https://app.codecov.io/github/Xabaril/AspNetCore.Diagnostics.HealthChecks/flags

Any help is welcome to write tests and increase code coverage.

[sungam3r]

With flags/carryforward codecov feature code coverage should be tracked per individual projects now.

[sungam3r]

Note - it seems that flags/carryforward feature works in unexpected way.