bugfix/3502 trusted host fails with custom port

[lbontecou]

Thank you for contributing to Pipenv!

The issue

#3502

Pipfile Source

---

[[source]]
name = "my-pypi"
url = "https://${PYPI_USERNAME}:${PYPI_PASSWORD}@${PYPI_HOSTNAME}:${PYPI_PORT}/simple"
verify_ssl = false

Bug Identification

---

$ pipenv install --skip-lock --verbose
...
$ ['.../bin/pip', 'install', '--verbose', '--upgrade', '${PACKAGE_NAME}', '-i', 'https://${PYPI_USERNAME}:${PYPI_PASSWORD}@${PYPI_HOSTNAME}:${PYPI_PORT}/simple', '--trusted-host', '${PYPI_HOSTNAME}', '--extra-index-url', 'https://pypi.org/simple']

The fix

How does this pull request fix your problem? Did you consider any alternatives? Why is this the best solution, in your opinion?

• Using the same library already in place, added logic to include port in the trusted-host argument.
• Consulted with docs to acknowledge alternative case where no port specified.
  https://urllib3.readthedocs.io/en/latest/reference/urllib3.util.html#urllib3.util.url.parse_url
  
• Unittest updates included

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 #.

[techalchemy]

Sorry for the delayed response, the changes look good to me, I'll merge them when they turn green! thanks for the pr