As there are quite some sniffs which now extend WPCS sniffs, it would be prudent to test builds against a mix of PHPCS and WPCS versions.
With the changes made in this PR, all sniffs will be tested against a combination of the highest PHPCS+WPCS versions as well as the lowest PHPCS+WPCS versions on most PHP versions.
To also make sure that the sniffs work correctly with a different combi, the PHP 7.2 build will test with high PHPCS vs low WPCS and with low PHPCS vs high WPCS.
As there are quite some sniffs which now extend WPCS sniffs, it would be prudent to test builds against a mix of PHPCS and WPCS versions.
With the changes made in this PR, all sniffs will be tested against a combination of the highest PHPCS+WPCS versions as well as the lowest PHPCS+WPCS versions on most PHP versions.
To also make sure that the sniffs work correctly with a different combi, the PHP 7.2 build will test with high PHPCS vs low WPCS and with low PHPCS vs high WPCS.