[MNT] Add dependency caching in CI

.github/workflows/main.yml

@@ -1,5 +1,8 @@
 name: Test and build mendeleev package
 
+env:
+  POETRY_VERSION: 1.8.2
+
 on:
   push:
     branches: [master]
@@ -24,24 +27,35 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
+
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
+
       - name: Install and configure Poetry
         uses: snok/install-poetry@v1
         with:
-          version: 1.8.2
+          version: ${{ env.POETRY_VERSION }}
           virtualenvs-create: true
           virtualenvs-in-project: true
+
+      - name: Cache dependencies
+        id: cache-deps
+        uses: actions/cache@v4
+        with:
+          path: ./.venv
+          key: pydeps-${{ matrix.os }}-python${{ matrix.python-version }}-${{ hashFiles('poetry.lock') }}
+
       - name: Install dependencies
+        if: steps.cache-deps.outputs.cache-hit != 'true'
         run: poetry install --with vis --no-interaction -v
+
       - name: Lint and format with ruff
         uses: pre-commit/[email protected]
+
       - name: Test with pytest
-        run: |
-          source $VENV 
-          pytest
+        run: poetry run pytest
 
   deploy:
     needs: test