Allow PureJuMP problems in generate meta

[tmigot]

using OptimizationProblems, NLPModels, NLPModelsJuMP
include("test/utils.jl")
name = "glider"
open("$name.jl", "w") do io
  print(io, generate_meta("$name"))
end

should now be possible to generate the Meta if we only have the JuMP model.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 99.73%. Comparing base (65bda82) to head (e1b52a7). Report is 6 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #329 +/- ## ========================================== - Coverage 99.82% 99.73% -0.10% ========================================== Files 1078 1078 Lines 12184 12183 -1 ========================================== - Hits 12163 12151 -12 - Misses 21 32 +11 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.