Add Dependabot configuration

Add configuration for Dependabot to automatically update dependencies,
if possible. Updates are currently managed to GitHub Actions as well as
Cargo.toml based Rust dependencies.

.github/dependabot.yml

@@ -0,0 +1,19 @@
+# Copyright (C) 2024 The apca Developers
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# Please see the documentation for all configuration options:
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+
+version: 2
+updates:
+ - package-ecosystem: github-actions
+ open-pull-requests-limit: 25
+ rebase-strategy: auto
+ directory: /
+ schedule:
+ interval: daily
+ - package-ecosystem: cargo
+ versioning-strategy: auto
+ directory: /
+ schedule:
+ interval: daily