Switch from /usr/bin to /usr/bin/env

[thinkverse]

This PR switches bin/gdaisy to use /usr/bin/env php instead of /usr/bin/php, this lets the end-users environment pick which PHP version to use via its PATH, as oppose to gdaisy pointing to a specific version.

For me, this fixes the issue of gdaisy using the built-in PHP 7.1 instead of my homebrew versions, causing me to manually change the vendor file directly to get it to work instead of throwing parse errors.

This is also an accepted practice, Laravel's artisan command uses this shebang, as well as Symfony in their Creating a Console Application example.

[erikaheidi]

Thank you!