Create sync-vercel-preview-branch.yml (#6)

Co-authored-by: Jonathan Fisher <[email protected]>

.github/workflows/sync-vercel-preview-branch.yml

@@ -0,0 +1,25 @@
+name: Sync master to vercel-preview
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  sync-branches:
+    runs-on: ubuntu-latest
+    name: Syncing branches
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Set up Node
+        uses: actions/setup-node@v1
+        with:
+          node-version: 12
+      - name: Opening pull request
+        id: pull
+        uses: tretuna/[email protected]
+        with:
+          GITHUB_TOKEN: ${{secrets.VERCEL_TOKEN}}
+          FROM_BRANCH: 'master'
+          TO_BRANCH: 'vercel-preview'