build: add GH workflow to sync alpha with master automatically (#2030)

.github/workflows/analyze-dependents.yml

@@ -280,9 +280,9 @@ jobs:
       uses: hmarr/auto-approve-action@v2
       with:
         pull-request-number: ${{ steps.cpr.outputs.pull-request-number }}
-        github-token: ${{ secrets.EDX_NETLIFY_PAT }}
+        github-token: ${{ secrets.requirements_bot_github_token }}
     - name: Auto-merge pull request for dependent project usages
       uses: pascalgn/automerge-action@v0.14.3
       env:
-        GITHUB_TOKEN: ${{ secrets.EDX_NETLIFY_PAT }}
+        GITHUB_TOKEN: ${{ secrets.requirements_bot_github_token }}
         MERGE_METHOD: squash

.github/workflows/sync-alpha-master.yml

@@ -0,0 +1,30 @@
+name: Sync alpha with master
+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: 18
+      - name: Create Pull Request
+        id: cpr
+        uses: tretuna/sync-branches@1.4.0
+        with:
+          GITHUB_TOKEN: ${{ secrets.requirements_bot_github_token }}
+          FROM_BRANCH: "master"
+          TO_BRANCH: "alpha"
+      - name: Enable Pull Request Auto Merge
+        uses: peter-evans/enable-pull-request-automerge@v2
+        with:
+          token: ${{ secrets.requirements_bot_github_token }}
+          pull-request-number: ${{ steps.cpr.outputs.PULL_REQUEST_NUMBER }}
+          merge-method: squash