Configure Dependabot to check for outdated Python package dependencies

Some of this project's tool dependencies are Python packages. In order to allow the project to benefit from ongoing
development of those dependencies, the maintainers must keep these packages updated.

This can be done in an efficient manner by using the Dependabot service.

Dependabot will periodically check the versions of all Python packages used by this project. If any are found to be
outdated, it will submit a pull request to update them.

Author: per1234

.github/dependabot.yml

@@ -11,3 +11,12 @@ updates:
       interval: daily
     labels:
       - "topic: infrastructure"
+
+  - package-ecosystem: pip
+    directory: /
+    schedule:
+      interval: daily
+    labels:
+      - "topic: infrastructure"
+    assignees:
+      - per1234