Update the trigger for Ubuntu 22.04

Author: shahmishal

docs/ContinuousIntegration.md

@@ -157,7 +157,7 @@ macOS platform | @swift-ci Please Sourcekit Stress test | Swift Sourcekit Stress
 Platform       | Comment | Check Status
 ------------   | ------- | ------------
 macOS platform | @swift-ci Please Build Toolchain macOS Platform| Swift Build Toolchain macOS Platform
-Linux platform | @swift-ci Please Build Toolchain Linux Platform| Swift Build Toolchain Linux Platform
+Linux platform | @swift-ci Please Build Toolchain Linux Platform| Swift Build Toolchain Ubuntu 22.04 (x86_64)
 
 You can also build a toolchain for a specific Linux distribution
 
@@ -166,6 +166,7 @@ Distro         | Comment                                   | Check Status
 UBI9           | @swift-ci build toolchain UBI9            | Swift Build Toolchain UBI9 (x86_64)
 CentOS 7       | @swift-ci build toolchain CentOS 7        | Swift Build Toolchain CentOS 7 (x86_64)
 Ubuntu 18.04   | @swift-ci build toolchain Ubuntu 18.04    | Swift Build Toolchain Ubuntu 18.04 (x86_64)
+Ubuntu 20.04   | @swift-ci build toolchain Ubuntu 20.04    | Swift Build Toolchain Ubuntu 20.04 (x86_64)
 Ubuntu 22.04   | @swift-ci build toolchain Ubuntu 22.04    | Swift Build Toolchain Ubuntu 22.04 (x86_64)
 Amazon Linux 2 | @swift-ci build toolchain Amazon Linux 2  | Swift Build Toolchain Amazon Linux 2 (x86_64)