update workflow for installed extension as well

Author: blink1073

{{cookiecutter.github_project_name}}/.github/workflows/build.yml

@@ -8,43 +8,21 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+        python-version: ["3.7", "3.10"]
     steps:
       - name: Checkout
         uses: actions/checkout@v2
-      - name: Install node
-        uses: actions/setup-node@v1
-        with:
-          node-version: "12.x"
-      - name: Install Python
-        uses: actions/setup-python@v2
-        with:
-          python-version: "3.7"
-          architecture: "x64"
 
-      - name: Setup pip cache
-        uses: actions/cache@v2
-        with:
-          path: ~/.cache/pip
-          key: pip-3.7-${{ hashFiles('package.json') }}
-          restore-keys: |
-            pip-3.7-
-            pip-
-
-      - name: Get npm cache directory
-        id: npm-cache
-        run: |
-          echo "::set-output name=dir::$(npm config get cache)"
-      - uses: actions/cache@v2
-        with:
-          path: ${{ steps.npm-cache.outputs.dir }}
-          key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
-          restore-keys: |
-            ${{ runner.os }}-node-
+      - uses: jupyterlab/maintainer-tools/.github/base-setup@v1
 
       - name: Install dependencies
         run: |
-          python -m pip install -U pip setuptools codecov
+          python -m pip install -U codecov
           npm install -g codecov
       - name: Test the extension
         run: |