Add code to update instances automatically.

.github/workflows/update-instances.yml

@@ -0,0 +1,22 @@
+name: Update Instance List
+
+on:
+  schedule:
+    - cron: "0 0 * * *" # Runs at 00:00 UTC every day
+  workflow_dispatch:
+
+jobs:
+  update:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+      - name: Install requirements
+        run: pip install -r requirements.txt
+      - name: Update Instances
+        run: python update-instances.py
+      - uses: EndBug/add-and-commit@v9
+        with:
+          default_author: github_actions
+          message: "Update instances"
+          add: ".upptimerc.yml"