Restore missing repo.py file (#6677)

Summary:
This was removed in #4833, I assume unintentionally. Unfortunate that we don't have a test on the 'prod' folder of deploy_docker, that would have caught this.

Test Plan: docker-compose build now passes

examples/deploy_docker/repo.py

@@ -0,0 +1,21 @@
+from dagster import job, op, repository, schedule
+
+
+@op
+def hello():
+    return 1
+
+
+@job
+def my_job():
+    hello()
+
+
+@schedule(cron_schedule="* * * * *", job=my_job, execution_timezone="US/Central")
+def my_schedule(_context):
+    return {}
+
+
+@repository
+def deploy_docker_repository():
+    return [my_job, my_schedule]