add dependabot (#25)

Co-authored-by: Luis Moreno <morenol@users.noreply.github.com>

Author: morenol

.github/dependabot.yml

@@ -0,0 +1,18 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: weekly
+
+  # Maintain dependencies for Cargo
+  - package-ecosystem: "cargo"
+    directory: "/"
+    schedule:
+      interval: weekly
+    ignore:
+      - dependency-name: "*"
+        update-types: [
+            "version-update:semver-minor",
+            "version-update:semver-patch",
+          ] # Only major version updates