build: Use dependabot to update github-actions

Stranger6667 · Stranger6667 · commit 1070716a511d · 2023-12-11T01:17:28.000+01:00
diff --git a/.github/dependabot.yml b/.github/dependabot.yml
@@ -1,5 +1,9 @@
 version: 2
 updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
   - package-ecosystem: "cargo"
     directory: "/css-inline"
     schedule:
