Script to check for outdated dependencies (GSI 371)

[TheByronHimes]

This adds a script (scripts/list_outdated_dependencies.py) that is meant to:

• List outdated capped dependencies based on what is specified.
• When used with --transitive, list outdated transitive dependencies based on what is pinned in the lock file.

It works by obtaining the latest version of a package from PyPI and seeing whether that version satisfies the version range we have specified.
Uncapped dependencies should therefore always be omitted by this method.

For example, if we required hexkit like this:
hexkit ~= 0.9.0
and the latest version on PyPI is 0.10.x, then the script will see that 0.10.x is not contained within the specifier ~= 0.9.0 and flag it as outdated.
If the specifier were uncapped, e.g. hexkit >= 0.9.0, then it would not be flagged as outdated because 0.10.x also satisfies >= 0.9.0.

Originally, this functionality was proposed to be included in the update_lock.py script. Even though some of the functionality is shared (e.g. examining a modified pyproject.toml), it would have been a shoehorn job. update_lock.py serves to resolve all project dependencies and update the lock files (and it takes some time), while the purpose of this script is to:

1. Highlight dependency specifiers that might need reconsideration
2. Display outdated transitive dependencies so we may see if any are so outdated that they warrant a second look at the associated top-level requirement(s).

[Cito]

Nice work.

Some suggestions below.

[github-actions]

Pull Request Test Coverage Report for Build 6381922761

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 0.0%

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Totals
Change from base Build 6336802662:	0.0%
Covered Lines:	0
Relevant Lines:	72

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💛 - Coveralls

[KerstenBreuer]

LGTM