docs: add client docs links (#37)

README.md

@@ -28,6 +28,15 @@ This repository contains the reference Swift client for the InfluxDB 2.0.
 - [Contributing](#contributing)
 - [License](#license)
 
+## Documentation
+
+This section contains links to the client library documentation.
+
+* [Product documentation](https://docs.influxdata.com/influxdb/v2.0/api-guide/client-libraries/), [Getting Started](#installation)
+* [Examples](Examples/README.md#examples)
+* [API Reference](https://influxdata.github.io/influxdb-client-swift/Classes/InfluxDBClient.html)
+* [Changelog](CHANGELOG.md)
+
 ## Features
 
 InfluxDB 2.0 client consists of two packages