Cache dependencies in Github Action (#1027) (#1028)

* Cache dependencies in Github Action. Fixes #1027

* Simplify key used for cache

Co-authored-by: Thomas Moreau <thomas.moreau.2010@gmail.com>

---------

Co-authored-by: Thomas Moreau <thomas.moreau.2010@gmail.com>

.github/workflows/tests.yml

@@ -37,6 +37,13 @@ jobs:
       with:
         python-version: ${{ matrix.python-version }}
 
+    - name: Cache dependency
+      id: cache-dependencies
+      uses: actions/cache@v4
+      with:
+        path: ~/.cache/pip
+        key: ${{ runner.os }}-pip
+
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip