Update changelog

Author: jflan-dd

CHANGELOG.md

@@ -14,6 +14,7 @@
 ## Master
 
 - Add Android support [@marcprux][] - [#635](https://github.com/danger/swift/pull/635)
+- Drain stdout and stderr concurrently [@jflan-dd] - [#636](https://github.com/danger/swift/pull/636)
 
 ## 3.20.2
 

Sources/DangerShellExecutor/ShellExecutor.swift

@@ -56,7 +56,7 @@ extension ShellExecuting {
 public struct ShellExecutor: ShellExecuting {
     /// Queue used to concurrently listen to both stdout and stderr
     private let outputQueue = DispatchQueue(label: "ShellExecutor.outputQueue", attributes: .concurrent)
-    
+
     public init() {}
 
     public func execute(_ command: String,