message: Add Azure Pipelines build badge
diff: <p align="center">
  <a href="https://circleci.com/gh/facebook/jest"><img src="https://circleci.com/gh/facebook/jest.svg?style=shield" alt="CircleCI Build Status"></a>
  + <a href="https://dev.azure.com/jestjs/jest/_build/latest?definitionId=1?branchName=master"><img src="https://dev.azure.com/jestjs/jest/_apis/build/status/facebook.jest?branchName=master" alt="Azure Pipelines Build Status"></a>
  <a href="https://travis-ci.org/facebook/jest"><img src="https://travis-ci.org/facebook/jest.svg?branch=master" alt="Travis Build Status"></a>
  <a href="https://ci.appveyor.com/project/Daniel15/jest/branch/master"><img src="https://ci.appveyor.com/api/projects/status/8n38o44k585hhvhd/branch/master?svg=true" alt="Windows Build Status"></a>
  <a href="https://codecov.io/gh/facebook/jest"><img src="https://codecov.io/gh/facebook/jest/branch/master/graph/badge.svg" alt="Codecov badge"></a>
  