Code Analysis: Add validate-pyproject.

[carlosperate]

Resource description

validate-pyproject - A command line tool and Python library for validating pyproject.toml files based on JSON Schema, and includes checks for PEP 517, PEP 518 and PEP 621.

By submitting this pull request I confirm I've read and complied with the below requirements

• [x] I have read and understood the Contribution Guidelines
• [x] I am making an individual pull request for each entry
• [x] I have added a useful title to the commit
• [x] I have added a useful title to this PR
• [x] I have added the new entry in alphabetical order
• [x] I have used the following format:

  - [Resource Title](link) - Resource short Description (2 lines or less in total)

• [x] The new entry meets one of these categories:
  • Is configured via its own tool sub-table in the pyproject.toml file (i.e., [tool.xxx])
  • Is a project template using the pyproject.toml file
  • Is an article about the pyproject.toml file
  • Is a link to a project discussion about pyproject.toml support