docs: Update README.md shields for changed CI

Signed-off-by: Gary Kim <[email protected]>

README.md

@@ -8,10 +8,7 @@
 [Installation](https://rclone.org/install/) |
 [Forum](https://forum.rclone.org/)
 
-[![Build Status](https://travis-ci.org/rclone/rclone.svg?branch=master)](https://travis-ci.org/rclone/rclone)
-[![Windows Build Status](https://ci.appveyor.com/api/projects/status/github/rclone/rclone?branch=master&passingText=windows%20-%20ok&svg=true)](https://ci.appveyor.com/project/rclone/rclone)
-[![Build Status](https://dev.azure.com/rclone/rclone/_apis/build/status/rclone.rclone?branchName=master)](https://dev.azure.com/rclone/rclone/_build/latest?definitionId=2&branchName=master)
-[![CircleCI](https://circleci.com/gh/rclone/rclone/tree/master.svg?style=svg)](https://circleci.com/gh/rclone/rclone/tree/master)
+[![Build Status](https://github.com/rclone/rclone/workflows/build/badge.svg)](https://github.com/rclone/rclone/actions?query=workflow%3Abuild)
 [![Go Report Card](https://goreportcard.com/badge/github.com/rclone/rclone)](https://goreportcard.com/report/github.com/rclone/rclone)
 [![GoDoc](https://godoc.org/github.com/rclone/rclone?status.svg)](https://godoc.org/github.com/rclone/rclone) 
 [![Docker Pulls](https://img.shields.io/docker/pulls/rclone/rclone)](https://hub.docker.com/r/rclone/rclone)