Msgs ordered differently in different runs

[uriii3]

Version of compliance checker running:
IOOS compliance checker version 5.1.1

Describe the checker this affects:
IOOS

Attach a minimal CDL or NetCDF file which is able to reproduce the issue
It doesn't allow me to attach the file.nc so I compressed it.
output_1.nc.zip

To Reproduce:
Run several times compliance-checker --test=cf:1.7 output_1.nc -f json and check the order of the messages in the output.

Describe the issue below:
It is supposed to have 2 warning messages on 2.5 Variables saying something about valid_min and valid_max. The problem is that in some runs it appears first the min and then the max and in another runs it is the other way around.
To check the output operationally this is not the best to have, as the message as a whole is actually different (maybe) in different cases.

[benjwadams]

Seems to apply to all checkers, not just JSON output.

[benjwadams]

Issue is due to use of sets and their lack of consistent ordering. PR should address this.

[uriii3]

Uh, perfect then! Thank you very much!

[uriii3]

Do we know when will this be merged on to the main branch? Thanks a lot in advance!