Update nlohmann/json library (fixes #284)

[tquatmann]

I re-applied the changes made to the old json version concerning RationalNumber support.

My changes to the main nlohmann/json release can be seen here

I briefly checked for obvious performance regressions, which does not seem to be the case.
Here some data, where I used storm-conv to parse and then export a ~38 MB JANI file from QVBS:

current main:

Command line arguments: --jani oscillators.8-10-0.1-1.jani --tojani test1 -jprop --compactjson
Current working directory: /Users/tim/git/qcomp/benchmarks/dtmc/oscillators

Parsing JANI input ...  done. (2.175s seconds).
Performing transformations on JANI model ...  done. (0.201s seconds).
Exporting JANI model ... Stored to file 'test1' done. (1.268s seconds).

This branch:

Command line arguments: --jani oscillators.8-10-0.1-1.jani --tojani test1 -jprop --compactjson
Current working directory: /Users/tim/git/qcomp/benchmarks/dtmc/oscillators

Parsing JANI input ...  done. (2.199s seconds).
Performing transformations on JANI model ...  done. (0.200s seconds).
Exporting JANI model ... Stored to file 'test1' done. (1.081s seconds).
?master ~/git/qcomp/benchmarks/dtmc/oscillators> 

[tquatmann]

I still need to add some documentation here before merging this.

[sjunges]

You are a true hero :-)

[sjunges]

Is there any reason why we did not specialize std::is_scalar_v in the changes within modernjson? That would have saved quite some lines in the diff?

Likewise, should we consider adding support for std::isfinite and some of the other number traits?

[sjunges]

Your changes in this PR LGTM

[tquatmann]

specialising is_scalar (and similar traits) would be great, but (quoting cppreference ):

The behavior of a program that adds specializations for std::is_scalar or std::is_scalar_v is undefined.

[tquatmann]

I made the json export a bit more robust (in case a huge storm::RationalNumber like 1E5000 might be converted to something like nan and/or inf.

I also added the promised documentation. From my side, this is ready to be merged :)

[sjunges]

LGTM!

[marisgg]

Hey, I thought I'd share the following; hopefully, this will help with debugging.

This Stormpy master fork fails (https://github.com/randriu/stormpy/actions/runs/6945132931/job/18893799741) on the latest version of Storm CI, possibly due to this PR. The error is inside CMakeFiles/utility.dir/src/utility/json.cpp.

I'm assuming this very recently started Stormpy build (https://github.com/moves-rwth/stormpy/actions/runs/6945494052/job/18894977397) will fail because of this.

[sjunges]

Looking at this, the problem is here: https://github.com/randriu/stormpy/blob/master/src/utility/json.cpp but I dont know where exactly. Maybe @tquatmann sees it?