Add GoFirmex in who-uses

[amantinetti]

Add GoFirmex in who-uses.json

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/docs.nestjs.com/blob/master/CONTRIBUTING.md

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Docs
• Other... Please describe:

What is the current behavior?

Add GoFirmex as a company using nestjs

Issue Number: N/A

What is the new behavior?

Add GoFirmex in Docs as a company using nestjs.

Does this PR introduce a breaking change?

• Yes
• No

Other information