Update and rename link-checker.yml to link-checker.yml.broken

Broken due to artifact obsolescence V1 and 2

Author: psonnera

.github/workflows/link-checker.yml renamed to .github/workflows/link-checker.yml.broken

@@ -20,10 +20,10 @@ jobs:
     steps:
       - uses: actions/checkout@v1
 
-      - name: Set up Python 4.0
+      - name: Set up Python 3.7
         uses: actions/setup-python@v2
         with:
-          python-version: "4.0"
+          python-version: "3.7"
 
       - name: Install packages
         run: |