Fix typos in code comments

[boldpulse]

Recently, I found out that there were 2 typos remaining in this project.

1. Here, my should be may.

https://github.com/TraceMachina/nativelink/blob/d37bd90a314890fe901235e0432d263faa66d221/deployment-examples/docker-compose/Dockerfile#L21

2. Here, the code comments for simple_cache_test.sh and simple_prometheus_test.sh are the same currently. For simple_prometheus_test.sh, the comment should be changed.

https://github.com/TraceMachina/nativelink/blob/d37bd90a314890fe901235e0432d263faa66d221/integration_tests/simple_cache_test.sh#L16

https://github.com/TraceMachina/nativelink/blob/d37bd90a314890fe901235e0432d263faa66d221/integration_tests/simple_prometheus_test.sh#L16