Run CI for Moodle up to 4.3.

[lucaboesch]

This adds the Moodle plugin CI tests for 4.2 and 4.3, too.

[timhunt]

To run moodle-plugin-ci, we are using server resource provided to us for free. I think we should not abuse that too much.

Also, ever CI run burns some energy, and the environment is in enough of a mess.

Therefore, I think we should not do so many runs. Normally, one run for each supported Moodle version is enough, and then distribute the PHP versions and DB types between those.

Also, please do not add PHPdoc to test_... methods. And never add @throws annotations.

[lucaboesch]

Fair enough, I'll shorten that down.
@Covers has to be added, else-wise we get a warning or error.
I can remove the @throws.

[timhunt]

@Covers \availability_quizquestion\question_list_fetcher is already present on the class. Generally, class -> class is the best granularity to specify coverage information (although there are exceptions). Your latest changes adds an unwanted blank line.

[lucaboesch]

That is indeed better. The @Covers wasn't needed at the function level.
I also removed the extra empty line.
Note that in regards to earlier in the day when i complained something might not work I found that I was on an older code base.
Might be worth so to increase the Plugin version number and add a new release to Moodle Plugin database, who knows.

Best,
Luca