Add option to reduce GitHub UI check marks

[davidmfinol]

Context

If a user has a lot of tests, they may be unable to use this action to display the test results through the GitHub UI.
They may run into the error: Only 65535 characters are allowed
Furthermore, even if they don't run into this error, they may not want to see a bunch of check marks when they are really only interested in seeing if any tests failed.

Suggested solution

Add an option to the unity-test-runner called githubCheckFailed, which, if enabled, would not show green check marks for each passing test case.
Instead, it would only show red crosses for each failed test.
If there are too many failed tests, it would perhaps take only the first few to show.

Considered alternatives

We could instead try to find a way to split the requests to the GitHub API into smaller pieces.
There may be a better name rather than githubCheckFailed

Additional details

This is to fix #142

[webbertakken]

Personally I feel we should use great defaults instead of creating another configuration option here.

We could do an automated check for the amount of tests and determine how to best display meaningful checks.

[MrGadget1024]

This is surely what I'm running into now - see #214