dependabot.yml: check for package updates monthly (#8975)

Co-authored-by: Axel Navarro <navarroaxel@gmail.com>

.github/dependabot.yml

@@ -0,0 +1,18 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "monthly"
+  - package-ecosystem: "npm"
+    directory: "/"
+    schedule:
+      interval: "monthly"
+  - package-ecosystem: "pip"
+    directory: "/"
+    schedule:
+      interval: "monthly"
+  - package-ecosystem: "pip"
+    directory: "/scripts/pdf"
+    schedule:
+      interval: "monthly"