Make sveltekit minor version flexible

[arieroos]

This is a potential fix for issue #37

I haven't tested it, I'm not sure exactly how to do that. However I figured that opening a PR is a way to get the ball rolling on fixing the issue.

I made the sveltekit version flexible so that the project can use the same sveltekit version as the user, as long as it is >= 1.8.3 and < 2.0.0
That should fix issue #37 and any future security warnings that may arise from a fixed sveltekit version.

[wbudd]

Temporary workaround using this ^1.8.3 fix suggested above by @arieroos:

1. npm uninstall sveltekit-adapter-aws (if currently installed)
2. Add the following lines to your project's (root level) package.json:

"overrides": {
  "sveltekit-adapter-aws": {
    "@sveltejs/kit": "^1.8.3"
  }
}

3. npm install -D sveltekit-adapter-aws

(Requires npm cli version 8.3.0 or newer.)