Port scie plugin to mainline

[sureshjoshi]

I've got a plugin that I've been using for about a year to package pexes into scie files using science.

I didn't mainline it because John mentioned that eventually pex will gain this functionality natively, so it seemed silly to port this in.

Today I realized, it's sillier to NOT port this in and then just eventually deprecate it in favour of the native tooling later. These are incredibly useful to me for non-docker deployments, and just making tooling easier on my machine (e.g. https://github.com/sureshjoshi/pantsible).

https://github.com/sureshjoshi/pants-plugins/tree/main/pants-plugins/experimental/scie
https://github.com/a-scie/jump
https://github.com/a-scie/science

[sureshjoshi]

Sounds like this might be coming sooner:
pex-tool/pex#2096 (comment)

[shanipribadi]

I am able to generate a scie pex by using the following configurations
note: the output in dist will not have the .pex extension

# BUILD
pex_binary(
    name="__main__",
    entry_point="__main__.py",
    extra_build_args=["--scie=eager"], # or lazy
    output_path="${spec_path_normalized}/${target_name_normalized}", # this template needs pants 2.23, on pants 2.22 have to write the file name without the .pex extension
    sh_boot=True,
    execution_mode="venv",
)

#pants.toml
[pex-cli]
version = "v2.20.1" # just to use the latest pex version, not sure the minimum needed
known_versions = [
  "v2.20.1|linux_x86_64|0dfc0295677698ad1c74c77e5f5b2ff19a0cba1ddd629b228aaf5d2bd290bc20|4313097",
]