Linking to "boazpoolman/strapi-plugin-config-sync" resolves to the
version of strapi-plugin-config-sync currently on master branch on
GitHub. Which prevents running tests in the playground against the local
version.
To make it easier to use the diff command in scripts and CI and to align
its API with POSIX diff and diffs on most systems exit with 1 when the
diff is not empty. Keep exiting with 0 when it is.
Fixes#66.
Running the tests repeatedly failed as the DB was left in an altered
state which interfered with the subsequent test invocation.
Remove the DB and generated config files after all the tests run.