fix linux build (#671)

.github/workflows/build.yml

@@ -23,6 +23,8 @@ jobs:
           # python that doesn't support unicode.  See:
           #   https://github.com/actions/setup-python/issues/23
 
+          sudo apt-get update
+
           sudo apt-get install python2.7
           python -m pip install --upgrade pip
 
@@ -113,6 +115,9 @@ jobs:
       - uses: actions/setup-python@v1
         with:
           python-version: '2.7.x'
+      - uses: actions/setup-node@v1
+        with:
+          node-version: '10.x'
       - name: download inkscape
         shell: bash
         run: |