ci: add size check integration (#2369)

.github/workflows/size-check.yml

@@ -0,0 +1,19 @@
+name: 'size'
+on:
+  pull_request:
+    branches:
+      - master
+jobs:
+  size:
+    runs-on: ubuntu-latest
+    env:
+      CI_JOB_NUMBER: 1
+    steps:
+      - uses: actions/checkout@v1
+      - uses: bahmutov/npm-install@v1
+
+      - uses: posva/size-check-action@v1.0.2
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          build_script: size
+          files: packages/vue/dist/vue.global.prod.js packages/runtime-dom/dist/runtime-dom.global.prod.js packages/size-check/dist/size-check.global.prod.js