Set up Python in main branch workflow file

.github/workflows/pkgdown-devel.yaml

@@ -31,6 +31,20 @@ jobs:
       - name: Install github version of scater
         run: remotes::install_github("Alanocallaghan/scater")
         shell: Rscript {0}
+      - name: Setup python
+        uses: actions/setup-python@v2
+        with:
+          python-version: '3.8'
+      - uses: actions/cache@v2
+        name: Configure pip caching
+        with:
+          path: ~/.cache/pip
+          key: ${{ runner.os }}-pip-${{ hashFiles('**/vig2ipynb_requirements.txt') }}
+          restore-keys: |
+            ${{ runner.os }}-pip-
+      - name: Install gget
+        run: |
+          python -m pip install gget
       - name: Build site
         run: pkgdown::build_site_github_pages(new_process = TRUE, install = FALSE)
         shell: Rscript {0}