[BUG] `$black` variable is missing from `daff-button` theme functions in ng11

[damienwebdev]

:bug: Bug report

Current Behavior

Currently, I can't set use the design library on latest Angular 11.

Expected Behavior

I expected the design library to work.

Minimal reproduction of the problem with instructions

I was following the getting started guide and I got the following error when I added the theme:

Error in node_modules/@daffodil/[email protected]/daff-theme.scss (2186:18)
Undefined variable.
╷
2186 │ 0 3px 5px rgba($black, 0.12),
│ ^^^^^^
╵
../node_modules/@daffodil/[email protected]/daff-theme.scss 2186:18 daff-raised-button-theme-variant()
../node_modules/@daffodil/[email protected]/daff-theme.scss 2381:3 daff-button-theme()
../node_modules/@daffodil/[email protected]/daff-theme.scss 3603:2 daff-theme()
../~/src/styles.scss 4:1 root stylesheet

Stackblitz

What is the motivation / use case for changing the behavior?

I tried to use the design library.

Environment

Daffodil version: 0.39.9
Angular version: 11.2.14