Update 01-creating-app.md - (change --vue2 to --vue-2)

[mlanning]

When running the command meteor create --vue2 simple-todos-vue --prototype, it returns --vue2: unknown option. The fix here is that the option should be --vue-2.

[CLAassistant]

All committers have signed the CLA.

[Grubba27]

Hey @mlanning, thanks again for your PR, the only thing that is missing is signing the CLA!

[mlanning]

@Grubba27 Signed ✅ Thank you!