Update CI in order to drop Node 8.x

Author: rodion-arr

.github/workflows/test.yml

@@ -1,11 +1,16 @@
 name: Test
-on: push
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
 jobs:
   test:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node-version: [8.x, 10.x, 12.x]
+        node-version: [10.x, 12.x, 14.x]
     steps:
     - uses: actions/checkout@v1
     - name: Use Node.js ${{ matrix.node-version }}