Update docker-compose.yml

[alberttwong]

Problem

albert@albertonehouse kafka-connect-datagen % docker compose up yaml: unmarshal errors: line 34: mapping key "KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR" already defined at line 32

Solution

Does this solution apply anywhere else?

• [ ] yes
• [x] no

If yes, where?

Test Strategy

Testing done:

• [ ] Unit tests
• [ ] Integration tests
• [ ] System tests
• [x] Manual tests

Release Plan

[confluent-cla-assistant[bot]]

:tada: All Contributor License Agreements have been signed. Ready to merge.
:white_check_mark: alberttwong
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