Update Dependabot config file

Author: dependabot-preview[bot]

.dependabot/config.yml

@@ -0,0 +1,10 @@
+version: 2
+updates:
+- package-ecosystem: pip
+  directory: "/"
+  schedule:
+    interval: monthly
+  open-pull-requests-limit: 10
+  allow:
+  - dependency-name: flake8
+  - dependency-name: black