Use opencover format for coverage reports.

[fiseni]

No description provided.

[Copilot]

Pull Request Overview

This PR switches the coverage report generation from Cobertura to OpenCover format.

• Adds Format=opencover to the dotnet test coverage collector.
• Updates reportgenerator input pattern from coverage.cobertura.xml to coverage.opencover.xml.

Comments suppressed due to low confidence (1)

coverage.sh:20

• Quote the $testtarget variable to prevent word splitting in shell, e.g., use "$testtarget".

dotnet test $testtarget --configuration Release --no-build --no-restore --framework net9.0 --collect:"XPlat Code Coverage;Format=opencover"