avoid start failure with multiple concurrent CI runs

Author: baggepinnen

.github/workflows/Documentation.yml

@@ -29,12 +29,11 @@ jobs:
           private_registry_name: JuliaHubRegistry
           private_registry_uuid: de52bcdf-fcb2-40cf-a397-3d64b64f4d9c
       - name: Install dependencies
-        run: DISPLAY=:0 xvfb-run -s '-screen 0 1024x768x24' julia --project=docs -e 'using Pkg;
-                                      ENV["DISPLAY"] = "0";
+        run: DISPLAY=:0 xvfb-run --auto-servernum -s '-screen 0 1024x768x24' julia --project=docs -e 'using Pkg;
                                       Pkg.setprotocol!(; domain = "github.com", protocol = "ssh"); 
                                       Pkg.develop(PackageSpec(path=pwd()));
                                       Pkg.instantiate()'
       - name: Build and deploy
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # For authentication with GitHub Actions token
-        run: DISPLAY=:0 xvfb-run -s '-screen 0 1024x768x24' julia --project=docs/ docs/make.jl
+        run: DISPLAY=:0 xvfb-run --auto-servernum -s '-screen 0 1024x768x24' julia --project=docs/ docs/make.jl