Widen o-colors dependency to earliest compatible version

Fixes an issue where a product had a cross dependency issue when loading:

https://build.origami.ft.com/bundles/css?modules=o-grid@^2.1.5,o-ft-icons@^2.2.2,o-ft-header@2.5.5,o-colors@2.3.17,o-ft-typography@1.12.2,o-ft-buttons@1.5.4,o-fonts@1.4.1