Fix fatal error from following "Creating a Browser App" instructions #23
Description
On an Intel Macbook, following the instructions at the bottom of Creating a Browser App to build the Tokamak demo app will result in a fatal error. To solve the issue, the .swift-version in the Tokamak directory needs to match the swift-wasm version on the user's machine.
It would be helpful/ease getting started to create a Note about this fatal error or link to this Issue.