fix: Vagrant syntax about private_network

[tongtie]

• OS: macOS 10.15.6
• vagrant: 2.2.18
• virtualbox: 6.1

I could not log in via plain ssh before, as shown below

After modifying the vagrantfile, I can log in with plain ssh

[geerlingguy]

Thanks! Seems like an odd one, maybe conflicts with something in particular instances, but not always, because the old syntax was working for me.

But I found that this is indeed the syntax used in Vagrant's docs nowadays — see https://developer.hashicorp.com/vagrant/docs/networking/private_network

I couldn't get the conflicts to resolve, but I did a search and replace for all instances of :private_network, and replaced them with "private_network",, which seems like it should work fine.