dependabot.yml: Add github-actions (#47)

Author: nietras

.github/dependabot.yml

@@ -6,9 +6,15 @@ updates:
   - package-ecosystem: "nuget"
     directory: "/"
     schedule:
-      interval: "weekly"
+      interval: "daily"
     # Create a group of dependencies to be updated together in one pull request
     groups:
-       BenchmarkDotNet:
-          patterns:
-            - "BenchmarkDotNet*"
+      BenchmarkDotNet:
+        patterns:
+          - "BenchmarkDotNet*"
+
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      # Check for updates to GitHub Actions every week
+      interval: "daily"