fix: same interpreter from venv to get pkg name

[lecardozo]

• I have added an entry to docs/changelog.md

Summary of changes

Fixes #956

• Use venv-specific interpreter for package name extraction when injecting local "pip-installable" packages

Test plan

Tested by running the following locally

pipx install jupyterlab --python python3.8

# The package must be any wheel with interpreter constraints
# that are compatible with the venv's in which it's going to be injected
# but doesn't match pipx's default interpreter
pipx inject jupyterlab package-1.0.0-py3-none-any.whl