Fix for Apache Licence header

[markmandel]

Apparently I applied the Apache header licence wrong to everything, so this is a fix for that so that now everything has the correct details.

[quilkin-bot]

Build Succeeded 🥳

Build Id: c15b9164-0e7d-4da9-ad68-8a9e3204e2fa

To build this version:

git fetch git@github.com:googleforgames/quilkin.git pull/302/head:pr_302 && git checkout pr_302
cargo build

[markmandel]

Thanks! and apologies for all the conflicts this is going to cause.