docs: Update README to point to GitHub Actions

Change-Id: I143c725923e9a321df22df97510b54e8f3c05cb2

Author: jeremyk-lunarg

README.md

@@ -3,10 +3,7 @@
 This project provides Khronos official Vulkan Tools and Utilities for Windows, Linux, Android, and MacOS.
 
 ## CI Build Status
-| Platform | Build Status |
-|:--------:|:------------:|
-| Linux/Android | [![Build Status](https://travis-ci.org/KhronosGroup/Vulkan-Tools.svg?branch=master)](https://travis-ci.org/KhronosGroup/Vulkan-Tools) |
-| Windows |[![Build status](https://ci.appveyor.com/api/projects/status/hwc1hy417hf42xnf?svg=true)](https://ci.appveyor.com/project/Khronoswebmaster/vulkan-tools/branch/master) |
+[![Build Status](https://github.com/KhronosGroup/Vulkan-Tools/workflows/CI%20Build/badge.svg?branch=master)](https://github.com/KhronosGroup/Vulkan-Tools/actions)
 
 
 ## Introduction