Add hacs validate action

Author: jwillemsen

.github/dependabot.yml

@@ -0,0 +1,8 @@
+# Set update schedule for GitHub Actions
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+

.github/workflows/validate.yml

@@ -0,0 +1,17 @@
+name: HACS Validate
+
+on:
+  pull_request:
+  schedule:
+    - cron: "0 0 * * *"
+
+jobs:
+  validate:
+    runs-on: "ubuntu-latest"
+    steps:
+      - uses: "actions/checkout@v2"
+      - name: HACS validation
+        uses: "hacs/action@main"
+        with:
+          category: "integration"
+          comment: false