Set relativeUrls option to false by default, like the less docs.

[kevinfrom]

Expected Behavior

relativeUrls to be false by default, just like the less docs says:

Actual Behavior

relativeUrls is true by default.

Steps to Reproduce the Problem

1. Use the plugin with default settings in any esbuild configuration.

Versions

• esbuild: 0.23.1
• esbuild-plugin-less: 1.3.8
• Platform: AlmaLinux 9.4 on WSL2, Node 14.21.3