Validate package name breaks with capitalize letters

Description

The new checks for package name don’t allow for capitalize letters, which has broken many themes I had installed.

To Reproduce…

Steps to reproduce the behavior:

  1. Install a theme that has any letter capitalized in its name

  2. See error

Expected Behavior

Capitalized letters in the theme name should not prevent installation

Setup

  • OS and Version: Ubuntu 24.04
    • Installation Method: .deb
  • Mailspring Version: 1.21.0

Additional Context

The following commit added checks to the package name to prevent some attacks, but allowing capitalized letters shouldn’t introduce any errors and keep backwards compatibility: