Fix failing badge on README

Summary: Badge on README showed failing because the github workflow name changed, so the previous badge was no longer valid.

Reviewed By: joesus

Differential Revision: D39627917

fbshipit-source-id: 2d632c89f18cbca7a448cbafcd70cd91c5f32a2d

README.md

@@ -1,6 +1,6 @@
 Facebook SDK for Android
 ========================
-![Verify build with gradle](https://github.com/facebook/facebook-android-sdk/workflows/Verify%20build%20with%20gradle/badge.svg)
+[![Run testsuite with gradle](https://github.com/facebook/facebook-android-sdk/actions/workflows/verifybuild.yml/badge.svg)](https://github.com/facebook/facebook-android-sdk/actions/workflows/verifybuild.yml)
 [![Maven Central](https://maven-badges.herokuapp.com/maven-central/com.facebook.android/facebook-android-sdk/badge.svg?style=flat)](https://maven-badges.herokuapp.com/maven-central/com.facebook.android/facebook-android-sdk)
 
 This open-source library allows you to integrate Facebook into your Android app.