Update documentation github workflow to work with GLMakie

Using xvfb, x virtual frame buffer

Author: Larbino1

.github/workflows/documentation.yml

@@ -21,10 +21,14 @@ jobs:
         with:
           version: '1'
       - uses: julia-actions/cache@v2
+      - name: Install virtual frame buffer
+        run: sudo apt-get update && sudo apt-get install -y xvfb
       - 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 }} # If authenticating with GitHub Actions token
           DOCUMENTER_KEY: ${{ secrets.DOCUMENTER_KEY }} # If authenticating with SSH deploy key
-        run: julia --project=docs/ docs/make.jl
+        run: >
+          DISPLAY=:0 xvfb-run -s '-screen 0 1024x768x24'
+          julia --project=docs/ docs/make.jl