feat(companies): change companies to startups

[FabrizioCafolla]

PR Checklist

• I have read the Contributing Guidelines on pull requests.
• I have read the Code of conduct.

If this is an added new project

• I created the "company-name.json" file in the awesome/companies/data folder and complied with the required fields
• I created the "project-name.json" file in the awesome/opensource/data folder and complied with the required fields
• I created the "communities-name.json" file in the awesome/communities/data folder and complied with the required fields
• I created the "digital-nomads-name.json" file in the awesome/digital-nomads/data folder and complied with the required fields
• The project you entered is still maintained and includes guidelines for use

If this is related to an issue/PR

• I documented and tested the code (issue #)