refs linear.app/tryghost/issue/CORE-74/improve-the-test-situation
- this commit adds the codecov GitHub Action into CI so we can upload
coverage reports
- the coverage files need to be in XML for them to work with
codecov, so this commit also adds cobertura (XML) as a reporter
This reverts commit c2707d426a.
The changes for 1.7.3 were reverted as a temporary step due to a major bug in Portal link handling.
This commit brings back the changes followed by a patch for new release
no refs
The master -> main rename was missed for test workflows as well as Readme badge, which caused the error reporting to incorrectly report passing tests on `master` while they were failing on `main`
