ci: Add dependabot configuration for monthly updates (#600)

Co-authored-by: Valérian Rey <31951177+ValerianRey@users.noreply.github.com>
Co-authored-by: opencode-agent[bot] <opencode-agent[bot]@users.noreply.github.com>

Author: 3 people

.github/dependabot.yml

@@ -0,0 +1,11 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "monthly"
+
+  - package-ecosystem: "pre-commit"
+    directory: "/"
+    schedule:
+      interval: "monthly"

.pre-commit-config.yaml

@@ -15,7 +15,3 @@ repos:
       - id: ruff-check
         args: [ --fix, --ignore, FIX ]  # Allow committing with TODOs. Only CI checks should prevent merging with TODOs.
       - id: ruff-format
-
-ci:
-    autoupdate_commit_msg: 'chore: Update pre-commit hooks'
-    autoupdate_schedule: quarterly