Add headless display server to CI

.github/workflows/Documentation.yml

@@ -18,10 +18,10 @@ jobs:
       - uses: julia-actions/setup-julia@latest
         with:
           version: '1.5'
+      - uses: GabrielBB/xvfb-action@v1
       - name: Install dependencies
         run: julia --project=docs/ -e 'using Pkg; Pkg.develop(PackageSpec(path=pwd())); Pkg.instantiate()'
       - name: Build and deploy
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: julia --project=docs/ docs/make.jl
-