Update documentation.yml

Build documentation on Julia 1.9

.github/workflows/documentation.yml

@@ -13,7 +13,7 @@ jobs:
       - uses: julia-actions/setup-julia@latest
         with:
           # Build documentation on Julia 1.9
-          version: '1'
+          version: '1.9'
       - name: Install dependencies
         run: julia --project=docs/ -e 'using Pkg; Pkg.develop(PackageSpec(path=pwd())); Pkg.instantiate()'
       - name: Build and deploy