fix github action

Author: jasongrout

.github/workflows/build.yml

@@ -15,20 +15,45 @@ jobs:
     - name: Install node
       uses: actions/setup-node@v1
       with:
-       node-version: '10.x'
+       node-version: '12.x'
     - name: Install Python
       uses: actions/setup-python@v1
       with:
         python-version: '3.8'
         architecture: 'x64'
+    - name: Cache pip on Linux
+      uses: actions/cache@v1
+      if: startsWith(runner.os, 'Linux')
+      with:
+        path: ~/.cache/pip
+        key: ${{ runner.os }}-pip-${{ matrix.python }}-${{ hashFiles('**/requirements.txt') }}
+        restore-keys: |
+          ${{ runner.os }}-pip-${{ matrix.python }}
+
+    - name: Get yarn cache directory path
+      id: yarn-cache-dir-path
+      run: echo "::set-output name=dir::$(yarn cache dir)"
+    - name: Cache yarn
+      uses: actions/cache@v1
+      id: yarn-cache # use this to check for `cache-hit` (`steps.yarn-cache.outputs.cache-hit != 'true'`)
+      with:
+        path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
+        key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
+        restore-keys: |
+          ${{ runner.os }}-yarn-
     - name: Install dependencies
-      run: python -m pip install --pre jupyterlab
+      run: |
+        python -m pip install --pre jupyterlab==3.0.0b7
+        python -m pip install jupyter_packaging
     - name: Build the extension
       run: |
-        jlpm
+        pip install .
+        jlpm install
         jlpm run build
         cd jupyterlab_widgets
-
-        jupyter labextension install .
+        pwd
+        pip install -e .
+        jupyter labextension develop . --overwrite
+        jupyter labextension list
 
         python -m jupyterlab.browser_check

jupyterlab_widgets/setup.py

@@ -65,7 +65,7 @@
     cmdclass= cmdclass,
     packages=setuptools.find_packages(),
     install_requires=[
-        "jupyterlab~=3.0.0b6",
+        "jupyterlab~=3.0.0b7",
     ],
     zip_safe=False,
     include_package_data=True,