Create Dependabot config file (#28)

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

.github/dependabot.yml

@@ -0,0 +1,7 @@
+version: 2
+updates:
+- package-ecosystem: composer
+ directory: "/"
+ schedule:
+ interval: monthly
+ open-pull-requests-limit: 10