Use hashed requirements lock

.github/workflows/python-ci.yml

@@ -59,14 +59,16 @@ jobs:
         uses: actions/cache@v3
         with:
           path: ~/.cache/pip
-          key: ${{ runner.os }}-pip-${{ hashFiles('src/requirements.txt') }}
+          key: ${{ runner.os }}-pip-${{ hashFiles('requirements.lock') }}
           restore-keys: |
             ${{ runner.os }}-pip-
-      - name: Set up Python dependencies
-        id: deps
+      - name: Verify lockfile and install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install -r src/requirements.txt
+          pip install pip-tools
+          pip-compile --generate-hashes --output-file=requirements.lock src/requirements.txt
+          git diff --exit-code requirements.lock
+          pip install --require-hashes -r requirements.lock
       - name: Run pip-audit
         run: |
           pip install pip-audit