Link to latest version of statamic 404s

Hey there 👋 
I noticed that [this link](https://github.com/statamic/v2-docs/blob/d710bf19a4fad7842d7140d87f236ac401910d88/content/collections/docs/installing.md#L107) in the docs 404s. To be fair, it's probably one of the coolest 404 page I've seen.

I'd also be happy to open a PR if someone could help direct on where it should point.