Update PlutoSliderServer

Author: goerz

.github/workflows/ExportPluto.yaml

@@ -43,7 +43,7 @@ jobs:
                 julia -e 'using Pkg
                   Pkg.activate(mktempdir())
                   Pkg.add([
-                    Pkg.PackageSpec(name="PlutoSliderServer", version="0.3.2-0.3"),
+                    Pkg.PackageSpec(name="PlutoSliderServer", version="1.3.1"),
                   ])
 
                   import PlutoSliderServer