Manually remove moodle-cs tests

This step will be needed until this PR:

moodlehq/moodle-cs#69

is merged and released. Then we can get rid of it. Note
the reason is that phpunit finds the tests under vendor
and tries to execute them. As far as moodle-cs is now
just a dependency we don't want it to contain any
developing code (ci, tests, docs...) in its distribution form.

readme_moodle.txt

@@ -32,9 +32,12 @@ To update any component:
 3. Switch to the lowest PHP version supported by the Moodle version required.
 4. Run `composer install` (to install everything).a
 5. Update `thirdpartylibs.xml` to annotate the new versions of the tools.
-6. Commit changes with details about the tools updated.
-7. Test, test, test.
-8. Optionally, release.
+6. Remove `vendor/moodlehq/moodle-cs/moodle/Tests`. Note that this step
+   will be removed once https://github.com/moodlehq/moodle-cs/pull/69
+   is released and we update to that version.
+7. Commit changes with details about the tools updated.
+8. Test, test, test.
+9. Optionally, release.
 
 At some point we may want to make the process above automated, so every time
 that a new moodle-cs package is released, everything above (1-8) happens automatically.