[a11y] color contrast

[brianteeman]

The gray color used in the breadcrumbs for inactive fails the contrast checks

.breadcrumb-item.active {
    color: #868e96;
}

An alternative that does pass is

.breadcrumb-item.active {
    color: #656b72;
}

Or we could use $gray-700: #495057 but that might be too dark

I havent submitted a pr as I am not sure of the knock on consequences of changing the colour in the scss files etc

[brianteeman]

No idea why I submitted this here as its a front end issue