Use nightly pandas builds again

yolo

Author: honno

.github/workflows/test.yml

@@ -10,14 +10,17 @@ jobs:
       uses: actions/setup-python@v2
       with:
         python-version: 3.8
+    - name: Upgrade pip
+      run: |
+        pip install pip --upgrade
     - name: Install dependencies
       run: |
         pip install -r requirements.txt
     - name: Install dataframe libraries
       run: |
         pip install ray git+https://github.com/modin-project/modin
         pip install vaex  # use stable as no nightly builds and long build time
-        pip install pandas --no-deps --ignore-installed  # use stable as erroneous nightly builds and long build time
+        pip install --pre --extra-index https://pypi.anaconda.org/scipy-wheels-nightly/simple pandas --ignore-installed -
     - name: Run tests
       run: |
         pytest tests/ -v --ci