ci: update Documenter action to run multithreaded

Author: wolthom

.github/workflows/Documentation.yml

@@ -26,4 +26,4 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # For authentication with GitHub Actions token
           DOCUMENTER_KEY: ${{ secrets.DOCUMENTER_KEY }} # For authentication with SSH deploy key
-        run: julia --project=docs/ docs/make.jl
+        run: julia -t=auto --project=docs/ docs/make.jl