[Feature Request] Set table-header-font-weight to 700 as default

[rauhur]

Problem to solve

Each heading title in each v-table and v-data table has a font-weight of 500, like the rest of the content. I consider this a problem as it does not allow to differentiate the headings from the content clearly.

Proposed solution

Set $table-header-font-weigh = 700 !default at src/components/VTable/_variables.scss file