GH Actions updates. (#29429)

.github/workflows/test.yml

-name: Run tests
+name: Tests
 on: [push, pull_request]
 
 jobs:
@@ -13,7 +13,7 @@ jobs:
 
     steps:
       - name: Clone repository
-        uses: actions/checkout@master
+        uses: actions/checkout@v1
         with:
           fetch-depth: 3
 

README.md

@@ -53,7 +53,7 @@ Read the [Getting started page](https://getbootstrap.com/docs/4.3/getting-starte
 
 ## Status
 
-![Build Status](https://action-badges.now.sh/twbs/bootstrap)
+![Build Status](https://github.com/twbs/bootstrap/workflows/Tests/badge.svg)
 [![npm version](https://img.shields.io/npm/v/bootstrap.svg)](https://www.npmjs.com/package/bootstrap)
 [![Gem version](https://img.shields.io/gem/v/bootstrap.svg)](https://rubygems.org/gems/bootstrap)
 [![Meteor Atmosphere](https://img.shields.io/badge/meteor-twbs%3Abootstrap-blue.svg)](https://atmospherejs.com/twbs/bootstrap)