add Qt on CI system

[ursfassler]

Summary

Execute Qt tests on CI.

Details

Adding Qt to the CI system.

Motivation and Context

The Qt tests are not run on the CI system because they are not found. We may not know about a broken state for a long time.

This is a base to add another fix for the latest Qt versions: https://github.com/ursfassler/cucumber-cpp/tree/fix-build-with-qt5.15.2.

How Has This Been Tested?

With the github action.

Types of changes

• Bug fix (in the CI system) (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality to not work as expected).

Checklist:

• It is my own work, its copyright is implicitly assigned to the project and no substantial part of it has been copied from other sources (including Stack Overflow). In rare occasions this is acceptable, like in CMake modules where the original copyright information should be kept.
• I'm using the same code standards as the existing code (indentation, spacing, variable naming, ...).
• I've added tests for my code.
• I have verified whether my change requires changes to the documentation
• My change either requires no documentation change or I've updated the documentation accordingly.
• My branch has been rebased to master, keeping only relevant commits.

[mpkorstanje]

Cheers! Would you mind looking at the appveyor tests too? If they're not duplicates of the current set of tests in GitHub?

[ursfassler]

The appveyor tests seem to use Qt, but only run on Windows. All of them fail during gem install bundle.
Is this what you asked for? Should we discuss the whole appveyor topic in a bug report?

[mpkorstanje]

That seems reasonable. Though I wouldn't know what to fix about it and wouldn't be able to contribute much. I'm mostly merging everything that looks reasonable to keep momentum going.