v1.5.0

• Breaking change:
  • Drop support for Ruby 3.2
    • Ruby 3.2 is (EOL)
    • parallel-2.1.0 requires ruby version >= 3.3
• Chore:
  • Fix ruby-vips backend colourspace casting error #206
  • Change the way version is included. Instead of including a module Version, directly add the VERSION constant in the PixelChart class. It could avoid namespace collision with that kind of generic name.