Correct EasyEngine update command - Behat tests

The update behat test according to current implementation generates a phar and after update it replaces itself with the existing published phar. Hence it downgrades in reality instead of upgrading to the latest version which has not yet been released. Thus, the subsequent tests use the stable released phar which replaced the original latest changes phar. Giving no meaning to the tests performed then after in checking if they are in any way breaking update functionality or anything else.

The tests need to be updated to use the stable released phar in start and then update itself to the phar made of latest changes.

Steps to update the test will be updated here or in comments later with the inputs from @rahulsprajapati and @kirtangajjar. Any suggestions for the same are welcome.