Added GitHub action for detecting broken links

Author: jaaufauvre

.github/workflows/broken-links.yml

@@ -0,0 +1,18 @@
+on:
+  push:
+    branches: master
+  schedule:
+    - cron: "0 16 * * *"
+name: broken links?
+jobs:
+  linkChecker:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Link Checker
+        id: lc
+        uses: peter-evans/link-checker@v1.2.2
+        with:
+          args: -v -r *.md
+      - name: Fail?
+        run: exit ${{ steps.lc.outputs.exit_code }}

README.md

@@ -1,5 +1,7 @@
 # mastercard-api-client-tutorial
 
+[![](https://github.com/Mastercard/mastercard-api-client-tutorial/workflows/broken%20links%3F/badge.svg)](https://github.com/Mastercard/mastercard-api-client-tutorial/actions?query=workflow%3A%22broken+links%3F%22)
+
 [Generating and Configuring a Mastercard API Client](https://developer.mastercard.com/platform/documentation/security-and-authentication/generating-and-configuring-a-mastercard-api-client/) explains how to generate and configure a simple API client for one of the APIs offered on the [Mastercard Developer portal](https://developer.mastercard.com/apis). 
 
 Languages used in this tutorial: Java, Python, NodeJS, Ruby, PHP and C#.