Build docs on ubuntu (#1257)

Author: Steven Silvester

.github/workflows/ci.yml

@@ -98,7 +98,7 @@ jobs:
           token: ${{ secrets.GITHUB_TOKEN }}
 
   test_docs:
-    runs-on: windows-latest
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
       - uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1