add python actions for OptimalTransport.jl

Author: ToucheSir

.github/workflows/Downstream.yml

@@ -23,6 +23,14 @@ jobs:
           - {user: JuliaOptimalTransport, repo: OptimalTransport.jl, group: All}
     steps:
       - uses: actions/checkout@v2
+      # for OptimalTransport.jl
+      - name: Install python
+        uses: actions/setup-python@v2
+        with:
+          python-version: '3.9'
+          architecture: ${{ matrix.arch }}
+      # for OptimalTransport.jl
+      - run: python -m pip install pot
       - uses: julia-actions/setup-julia@v1
         with:
           version: ${{ matrix.julia-version }}