docs: update license and readme

Author: gamemaker1

LICENSE

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+# MIT License
+
+Copyright (c) 2023 Express Rate Limit
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.md

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+# <div align="center"> `RateLimit` Header Parser </div>
+
+<div align="center">
+
+[![tests](https://github.com/express-rate-limit/ratelimit-header-parser/actions/workflows/ci.yaml/badge.svg)](https://github.com/express-rate-limit/ratelimit-header-parser/actions/workflows/ci.yaml)
+[![npm version](https://img.shields.io/npm/v/ratelimit-header-parser.svg)](https://npmjs.org/package/ratelimit-header-parser 'View this project on NPM')
+[![npm downloads](https://img.shields.io/npm/dm/ratelimit-header-parser)](https://www.npmjs.com/package/ratelimit-header-parser)
+
+This library parses `RateLimit` headers of various forms into a normalized
+format. It supports the combined format specified in
+[draft 7](https://datatracker.ietf.org/doc/html/draft-ietf-httpapi-ratelimit-headers-07)
+of the
+[IETF Rate Limit Headers standard](https://github.com/ietf-wg-httpapi/ratelimit-headers),
+the uncombined `RateLimit-*` format of earlier drafts, traditional
+`X-RateLimit-*` headers, and a few other formats.
+
+</div>
+
+## Usage
+
+```ts
+import { parseRateLimit } from 'ratelimit-header-parser'
+
+const response = await fetch(
+	'https://api.github.com/repos/express-rate-limit/express-rate-limit/contributors?anon=1',
+)
+
+console.log('github ratelimit:', parseRateLimit(response))
+// > github ratelimit: { limit: 60, used: 1, remaining: 59, reset: 2023-08-25T04:16:48.000Z }
+```
+
+For more examples, take a look at the [`examples/`](examples/) folder.
+
+## API
+
+### `parseRateLimit(responseOrHeaders, [options]) => object | undefined`
+
+Scans the input for ratelimit headers in a variety of formats and returns the
+result in a consistent format, or undefined if it fails to find any rate-limit
+headers. Returns an object with the following fields, or `undefined` if it does
+not find any rate-limit headers.
+
+```ts
+type RateLimitInfo = {
+	limit: number
+	used: number
+	remaining: number
+	reset: Date | undefined
+}
+```
+
+#### `responseOrHeaders`
+
+> A node-style or fetch-style `Response`/`Headers` object.
+
+#### `options`
+
+> Options that configure how the library parses the headers.
+
+```ts
+type Options = {
+	// How to parse the `reset` field. If unset, the parser will guess based on
+	// the content of the header.
+	reset: |
+		'date' | // Pass the value to `new Date(...)` to let the JavaScript engine parse it.
+		'unix' | // Treat the value as the number of seconds since January 1, 1970 (A.K.A a UNIX epoch timestamp).
+		'seconds' | // Treat the value as the number of seconds from the current time.
+		'milliseconds' | // Treat the value as the number of milliseconds from the current time.
+}
+```
+
+## Issues and Contributing
+
+If you encounter a bug or want to see something added/changed, please go ahead
+and
+[open an issue](https://github.com/nfriexpress-rate-limitedly/ratelimit-header-parser/issues/new)!
+If you need help with something, feel free to
+[start a discussion](https://github.com/express-rate-limit/ratelimit-header-parser/discussions/new)!
+
+If you wish to contribute to the library, thanks! First, please read
+[the contributing guide](contributing.md). Then you can pick up any issue and
+fix/implement it!
+
+## License
+
+MIT © Express Rate Limit