Set the supported compatibility date to a week in the future #6008
Description
A user installing the latest version of Wrangler and workerd and setting their compat date to "today" should have no warnings or errors. Today, this will warn because the version of workerd installed will always have a latest supported compat date of a few days ago.
This assumes that no new flags will be added and then immediately default on within the space of a week, which seems to be a reasonable assumption.
For reference, cloudflare/workers-sdk#2385 is emblematic of the DX problems that we see today, where a fresh project gets warnings/errors relating to compat date that aren't actionable.