Have makefile list all avalible targets when no target specified

[jackinloadup]

make will now list all available targets when no target is specified :+1:

The following is an example output

user@localhost$ make
Please specify a target. See README for information about targets.
-> init
-> init-drupal
-> update
-> safe-update
-> docker-rebuild
-> docker-status
-> docker-start
-> docker-stop
-> composer-install
-> composer-update
-> drupal-upgrade
-> drupal-install
-> config-init
-> config-import
-> config-export
-> config-validate
-> config-refresh
-> salt
-> clear-cache
-> destroy
-> rebuild
-> ready
-> lint
-> sniff
-> code-test
-> code-fix
-> fix-permissions