Upgrade Terraform AWS provider to v4.x

[ofhouse]

Changes

• Rewrite S3 config to use the new resources
• Update examples

Fixes #286.

[khuezy]

This error is occurring in the last few PRs:

 Module not found: Error: Can't resolve 'encoding' in '/tmp/39a10d8/node_modules/node-fetch/lib

Is there some caching issue w/ the build pipeline?

[ofhouse]

@khuezy No, not a caching-issue.
The error is caused when building a text fixture that uses Next.js 7 (which is pretty old 😅).

Don't know why this issue occurred now since the affected packages isomorphic-unfetch & node-fetch were not updated recently.
However adding the encoding dependency solves the issue: af6548e

Another change made by the Vercel team recently when jumping from v12.1.2 to v12.1.3 was the introduction of route manifest version 4 (was 3 before).
Since our builder expects a version <= 3 it crashed during the build for the recent builds, this will be fixed in #292.