add composite action test case

.github/actions/install/action.yml

@@ -0,0 +1,13 @@
+name: install npm packages
+description: Installs npm packages
+
+runs:
+  using: composite
+  steps:
+    - name: Install Yarn
+      run: npm install -g yarn
+      shell: bash
+
+    - name: install packages if cache miss
+      run: yarn install safedep-test-pkg
+      shell: bash

.github/workflows/persistent-proxy-e2e.yml

@@ -89,6 +89,9 @@ jobs:
           python -m pip install safedep-test-pkg
           deactivate && rm -rf venv
 
+      - name: Install Dependencies from composite
+        uses: ./.github/actions/install
+
       - name: Stop proxy
         if: always()
         run: pmg proxy stop