Relax dependencies

[Fenntasy]

Description

Following #696 it seems it's not possible at the moment (and for a long time dependabot/dependabot-core#2165) to have two update channels so let's only keep production dependencies.

Types of changes

• Chore (non-breaking change which refactors / improves the existing code base)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to
  change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• My change requires a change to a package version.
• I have updated the package.json version accordingly.
• I have updated the CHANGELOG.md version accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[GrosboillotFlo]

"Until next time"!