This change replaces various cases in which installed distribution and
file look-ups used path searches with importlib.metadata backed
look-ups.

This fixes issues with `dist-info` lookup for PEP610 implementation as
well as `.pth` file look-up and `dist-info` removal.

* tests: add case for transitive markers propagation

Relates-to: #3878

* deps: update poetry-core

Relates-to: #3878

* env: ignore warnings when executing python scripts

When executing python scripts with an intent to deserialise via
`json.loads` we need to ensure we ignore warnings. This is required
because, warnings can cause a `JSONDecodeError`.

Resolves: #3897

* ci: use current source if experimental

text taken from https://github.com/python-poetry/poetry/releases/tag/1.1.5

* Used pyupgrade to remove compatibility code

May fix #3860

Resolves: #3842

discordapp.com domain will go defunct very soon, everything has transitioned to discord.com now

https://support.discord.com/hc/en-us/articles/360042987951-Discordapp-com-is-now-Discord-com

Replace updates of os.environ with explcit passing of `env` to
subprocess calls.

Relates-to: #3199