Use distribution to find path of installed pipenv.

[matteius]

The issue

Now that we dropped support for python 3.6 we should migrate away from pkg_resoruces as

Use of pkg_resources is discouraged in favor of importlib.resources, importlib.metadata

The fix

Start chipping away at our direct pkg_resoruces usages.

The checklist

• [ ] Associated issue
• [ ] A news fragment in the news/ directory to describe this fix with the extension .bugfix, .feature, .behavior, .doc. .vendor. or .trivial (this will appear in the release changelog). Use semantic line breaks and name the file after the issue number or the PR #.