feat(action): add dependabot

Signed-off-by: Vincent Koppen <[email protected]>

Author: vincentkoppen

.github/dependabot.yml

@@ -0,0 +1,11 @@
+# SPDX-FileCopyrightText: Contributors to the Power Grid Model project <[email protected]>
+#
+# SPDX-License-Identifier: MPL-2.0
+
+
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"