add Project flag to julia engine

[BeastyBlacksmith]

this would need to be disabled for julia versions below 0.7. How could I do this?
Addresses #157.

[gpoore]

The current system has no support for conditionally adding flags. One option would be to drop support for Julia <0.7. Another option would be to run julia --version whenever Julia is used, and if version <0.7 then strip out the --project=@.. This would have to be done in the Python code that assembles everything for running the subprocess. A final option would be to modify the template system to support version-based flags, but that's probably a much larger project. (I may look into that option for Codebraid, since its code-execution system may eventually replace PythonTeX's current code-execution system.)

Do you have any sense of how often --project=@. is useful versus how often older versions of Julia are still in use? My inclination would be to drop support for older versions since that's simple and 0.7 has been out for a little over a year. But it's definitely possible to keep compatibility.

[BeastyBlacksmith]

I think that flag is very useful since I don't have to have every package of all documents in the global environment. It also makes collaboration easier.
Personally I rarely read about people still using 0.6.4, but the only way to figure out how many use older versions and pythontex would be to try it out and see if anyone complains about it ^^.
Maybe making a branch that people who do happen to be in this group can check out would be a good idea.

[tawheeler]

I think dropping support for anything pre 1.0 at this point is acceptable.

[mykelk]

Agreed. Much easier to just drop pre 1.0. It isn't really supported anymore.

[BeastyBlacksmith]

@gpoore Since we are currently at Julia 1.4 with 1.5 on the way and the LTS version is 1.0.x, this would help with making good use of environments

[carstenbauer]

@gpoore Is it possible to get a new release tagged? We need this flag over at sisl/tufte_algorithms_book#24.

[gpoore]

@crstnbr @mykelk Just wanted to let you know that I haven't forgotten about this. I'm finalizing the next version of fvextra, which PythonTeX uses internally for code typesetting, and then releasing a new version of PythonTeX is next on my list.

[mykelk]

Great! Thanks!

[carstenbauer]

@gpoore any update on when there will be a new release?

[gpoore]

@crstnbr Thanks for the reminder. I just released v0.18. It will probably be a few days before CTAN is updated and it's available through TeX package managers.