feature: automatically sync fork from the original repo

.github/workflows/main.yml

@@ -1,16 +1,19 @@
 name: "Genshin Impact Helper"
 
 on:
-  workflow_dispatch:
   schedule:
-    - cron: "0 22 * * *"
+    - cron: "0 22 * * *"  # scheduled at 06:00 (UTC+8) everyday
+  workflow_dispatch:
 
 jobs:
   build:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - name: Checkout master
+        uses: actions/checkout@v2
+        with:
+         ref: master
 
       - name: Set up python
         uses: actions/setup-python@v2

.github/workflows/sync.yml

@@ -0,0 +1,19 @@
+name: "Auto Sync Fork"
+
+on:
+  schedule:
+    - cron: "0 */3 * * *"  # every 3 hours
+  workflow_dispatch:
+
+jobs:
+  sync:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Fork sync
+        uses: tgymnich/fork-sync@v1.2
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          owner: y1ndan
+          base: master
+          head: master