Use lowercase characters in example URL

[diegoviola]

A lot of projects seem to copy-paste the example config from https://editorconfig.org and then spend some extra time/effort to lowercase the URL.

Some examples:

• https://gitlab.archlinux.org/pacman/pacman/-/commit/24455cc5b206cc1dd783a6e219d506019ffee877
• https://gitlab.archlinux.org/archlinux/mkinitcpio/mkinitcpio/-/blob/master/.editorconfig?ref_type=heads#L2
• https://github.com/gentoo/gentoo/blob/master/.editorconfig#L1

This is just my attempt to save that extra effort.

[diegoviola]

@xuhdev Thank you!