🎨Reuse existing requirement pins @ smoke-test

.github/workflows/self-smoke-test-action.yml

@@ -48,8 +48,14 @@ jobs:
     timeout-minutes: 2
 
     steps:
+    - name: Check out the action locally
+      uses: actions/checkout@v3
+      with:
+        path: test
     - name: Install the packaging-related tools
       run: python3 -m pip install build twine
+      env:
+        PIP_CONSTRAINT: test/requirements/runtime.txt
     - name: Create the stub package importable directory
       run: mkdir -pv src/test_package
     - name: Populate the stub package `__init__.py`
@@ -77,10 +83,6 @@ jobs:
       env:
         TWINE_USERNAME: ${{ env.devpi-username }}
         TWINE_PASSWORD: ${{ env.devpi-password }}
-    - name: Check out the action locally
-      uses: actions/checkout@v3
-      with:
-        path: test
     - name: ✅ Smoke-test the locally checked out action
       uses: ./test
       with: