Every time we release a new version, the integration tests start failing. This
is because we have a CLI test where we look at the output of the tailwindcss --help output.

This output contains a version number, that will be out of date when we release a new version.

This PR fixes that by making the version dynamic based on the package.json
version value. This should be safe to do because the goal of the tests is
ensuring that the CLI help output is consistent, not so much the version
number. BUT it is still important that the version is in sync. This will ensure
it is always in sync.