(#407) Retain CollapseButton CSS

The CSS for the CollapseButton was getting deleted and needed to be added
to the safelist for purgeCSS. Now, with this in place, all buttons show
as they should with the correct styles.

Author: st3phhays

build/data/repository-config.ts

@@ -79,7 +79,8 @@ export const astroRepositoryConfig = {
             /^text-bg-(info|warning|danger|success)/,
             /^data-bs-popper/,
             /^ratio-/,
-            /^callout-/
+            /^callout-/,
+            /^btn-(primary|danger|success)/
         ]
     },
     root: './'