Fix typos in code comments

[boldpulse]

Description

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

Fixes #1189

Type of change

Please delete options that aren't relevant.

• [x] Bug fix (non-breaking change which fixes an issue)
• [x] This change requires a documentation update

Checklist

• [x] Updated documentation if needed
• [x] bazel test //... passes locally
• [x] PR is contained in a single commit, using git amend see some docs

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This change is 

[boldpulse]

Just caught simple issues. cc: @allada, @MarcusSorealheis

Waiting for reviews on my previous submitted issues and wanna work on more issues. :)

[boldpulse]

Rebased. cc: @aaronmondal, @MarcusSorealheis

[boldpulse]

Hope you to merge this. cc: @allada, @MarcusSorealheis, @aaronmondal