Widen @aws-appsync/eslint-plugin peer dep range to include eslint 10

### Summary

`@aws-appsync/eslint-plugin@2.0.2` declares its `eslint` peer dependency as:

```json
"peerDependencies": {
"eslint": "^8.57.0 || ^9.0.0"
}
```

This causes ERESOLVE failures on npm install for projects that have upgraded to ESLint v10, even though the plugin appears to
be runtime-compatible.

Why I believe v10 compatibility is already there

I inspected lib/index.js in the published tarball. The plugin:

- Imports only @typescript-eslint/parser from the eslint ecosystem — no eslint internals, no Linter, no rule-tester used at
runtime.
- Exports flat-config-shaped configs (plugin.configs.recommended uses plugins / languageOptions / rules), which is the shape
ESLint v9+ consumes natively.
- Each rule file is a standard ESLint rule object (meta + create) that uses only the public rule API.

There's nothing I can see that would break on v10.

### Verification

With npm install --legacy-peer-deps to bypass the peer check, I'm running the plugin successfully under:

- eslint@10.1.0
- @typescript-eslint/parser@8.58.0
- NodeJS 24.14.1

eslint --print-config confirms all 22 @aws-appsync/* rules are applied to matched resolver files, and lint runs complete without errors against our resolver sources.

### Requested change

Widen the peer range to include v10:

```json
"peerDependencies": {
"eslint": "^8.57.0 || ^9.0.0 || ^10.0.0"
}
```

Inspect the package metadata that defines the eslint peerDependencies and compare it with lib/index.js, which the report identifies as the runtime entry point. Test installation and linting with eslint@10.1.0 and @typescript-eslint/parser@8.58.0, including eslint --print-config on resolver files. Done means npm install succeeds without --legacy-peer-deps and all 22 rules remain applied without errors.

Written by the indexing model from the issue text.