Use conda in docs CI

.github/workflows/ci.yml

@@ -35,10 +35,10 @@ jobs:
                 python-version: '3.x'
         -   name: "Main Script"
             run: |
-                EXTRA_INSTALL="pybind11 numpy mako"
+                CONDA_ENVIRONMENT=.test-conda-env-py3.yml
                 curl -L -O -k https://gitlab.tiker.net/inducer/ci-support/raw/master/ci-support.sh
                 . ci-support.sh
-                build_py_project_in_venv
+                build_py_project_in_conda_env
                 build_docs
 
     pytest3: