fix lint issue

Author: martijnrusschen

src/stylesheets/variables.scss

@@ -17,6 +17,7 @@ $datepicker__border: 1px solid $datepicker__border-color;
 $datepicker__border-radius: 0.3rem !default;
 $datepicker__day-margin: 0.166em !default;
 $datepicker__font-size: 0.8rem !default;
+// stylelint-disable-next-line scss/dollar-variable-colon-space-after
 $datepicker__font-family:
   "Helvetica Neue", helvetica, arial, sans-serif !default;
 $datepicker__item-size: 1.7em !default;