update README

Author: ezhang6811

instrumentation/faraday/README.md

@@ -19,6 +19,7 @@ To install the instrumentation, call `use` with the name of the instrumentation.
 ```ruby
 OpenTelemetry::SDK.configure do |c|
   c.use 'OpenTelemetry::Instrumentation::Faraday'
+  suppress_internal_instrumentation: true
 end
 ```
 
@@ -30,6 +31,11 @@ OpenTelemetry::SDK.configure do |c|
 end
 ```
 
+### Configuration options
+This instrumentation offers the following configuration options: 
+* `suppress_internal_instrumentation` (default: `false`): When set to `true`, any spans with 
+ span kind of `internal` are suppressed from traces.
+
 ## Examples
 
 Example usage of faraday can be seen in the `./example/faraday.rb` file [here](https://github.com/open-telemetry/opentelemetry-ruby-contrib/blob/main/instrumentation/faraday/example/faraday.rb)