CI: Run Dependabot once a month, but increase the "open PR limit" (#136)

Author: DilumAluthge

.github/dependabot.yml

@@ -1,7 +1,10 @@
-# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
 version: 2
 updates:
   - package-ecosystem: "github-actions"
-    directory: "/" # Location of package manifests
+    directory: "/"
     schedule:
-      interval: "weekly"
+      interval: "monthly"
+    open-pull-requests-limit: 100
+    labels:
+      - "dependencies"
+      - "github-actions"