fix: add RSR-compliant dependabot config with common ecosystems

Author: hyperpolymath

.github/dependabot.yml

@@ -1,11 +1,48 @@
-# To get started with Dependabot version updates, you'll need to specify which
-# package ecosystems to update and where the package manifests are located.
-# Please see the documentation for all configuration options:
-# https://docs.github.com/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file
+# SPDX-License-Identifier: AGPL-3.0-or-later
+# Dependabot configuration for RSR-compliant repositories
+# Covers common ecosystems - remove unused ones for your project
 
 version: 2
 updates:
-  - package-ecosystem: "" # See documentation for possible values
-    directory: "/" # Location of package manifests
+  # GitHub Actions - always include
+  - package-ecosystem: "github-actions"
+    directory: "/"
     schedule:
-      interval: "daily"
+      interval: "weekly"
+    groups:
+      actions:
+        patterns:
+          - "*"
+
+  # Rust/Cargo
+  - package-ecosystem: "cargo"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    ignore:
+      - dependency-name: "*"
+        update-types: ["version-update:semver-patch"]
+
+  # Elixir/Mix
+  - package-ecosystem: "mix"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+
+  # Node.js/npm
+  - package-ecosystem: "npm"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+
+  # Python/pip
+  - package-ecosystem: "pip"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+
+  # Nix flakes
+  - package-ecosystem: "nix"
+    directory: "/"
+    schedule:
+      interval: "weekly"