ci: Add dependabot configuration for monthly updates

.github/dependabot.yml

@@ -0,0 +1,21 @@
+version: 2
+updates:
+  - package-ecosystem: "pip"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    groups:
+      dependencies:
+        patterns:
+          - "*"
+    open-pull-requests-limit: 5
+
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    groups:
+      actions:
+        patterns:
+          - "*"
+    open-pull-requests-limit: 5