Update help flag in CLI for UUID

[bfpepper87sentry]

Problem Statement

The way the help flag reads for the UUID makes it seem that it is optional. Though, technically, it is, the UUID is computed too late in the build process. And it is advisable that the user manually generate the UUID earlier in the process. The help flag reads:

sentry_cli upload-proguard -h
…

--uuid
Explicitly override the UUID of the mapping file with another one.
This should be used with caution as it means that you can
upload multiple mapping files if you don't take care. This
however can be useful if you have a build process in which you
need to know the UUID of the proguard file before it was
created. If you upload a file with a forced UUID you can only
upload a single proguard file.

is it possible to update this to let the user know that manually generating the UUID is a better option.

Solution Brainstorm

No response

[markushi]

@bfpepper87sentry thanks for the feedback!
Our Android docs already describe the step of supplying the UUID, but we should update the sentry-cli help message too.