Add cronjob for periodically updating website with new information from contentful

Author: andydevs

.github/workflows/cd.yml

@@ -2,6 +2,8 @@ name: Continuous Deployment
 on:
   push:
     branches: [master]
+  schedule:
+    - cron: '0 0 1 DEC,MAR,JUN,SEP *'
   workflow_dispatch:
 jobs:
   # Build