fix: Fixed dictionary keys changed during iteration" error in PoetryPyprojectHandler.set_path_dependencies_to_version() which seems to be caused by tomlkit even when modifying an existing key but setting it to a different value/type

[NiklasRosenstein]

It seems tomlkit containers behave a bit differently in that you can't even update an existing key's value during iteration. The following snippet demonstrates what caused this bug:

import tomlkit

data = tomlkit.loads("""
[package]
version = "1.0"
""")

for key in data.keys():
    data[key] = "bar"