fix(setup): remove boolean constraint from start flag

no issue
- if the boolean constraint is enabled, then argv.start will be false in the case that `--no-start` is provided OR neither `--start` nor `--no-start` is passed. This change makes the functionality work as intended

Author: acburdine

lib/commands/setup.js

@@ -189,8 +189,7 @@ SetupCommand.description = 'Setup an installation of Ghost (after it is installe
 SetupCommand.params = '[stages..]';
 SetupCommand.options = {
     start: {
-        description: '[--no-start] Enable/disable automatically starting Ghost',
-        type: 'boolean'
+        description: '[--no-start] Enable/disable automatically starting Ghost'
     },
     local: {
         alias: 'l',