Progress bars without color modifier are not visible in Darkly theme

[DJWoodZ]

Hi,

Thank you for this great project!

In the current version (0.7.1), Darkly themed progress bars without a color modifier (e.g. is-primary) do not display progress. An example can be seen here: https://jenil.github.io/bulmaswatch/darkly/#progress

I believe this is because $grey is used for both the background and default bar color.

[jenil]

Hey,

Thanks for reporting this. Yes I believe it is because of the recent updates, I'll fix it.