Add GitHub Actions workflows for CI

Author: ZenanH

.github/workflows/documentation.yml

@@ -26,5 +26,5 @@ jobs:
       - name: Build and deploy
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # If authenticating with GitHub Actions token
-          DOCUMENTER_KEY: ${{ secrets.DOCUMENTER_KEY }} # If authenticating with SSH deploy key
+          DOCUMENTER_KEY: ${{ secrets.DOCUMENTER_KEY }} # If authenticating with SSH deploy key 
         run: julia --project=docs/ docs/make.jl