[gnome-bootstrap-theme] chore: no longer uses webpack

[Guillaume Bernard <gbernard src gnome org>]

commit 86d0dbdc38e21c7e691a7c6dcb6705c58b6fca60
Author: Guillaume Bernard <associations guillaume-bernard fr>
Date:   Fri Sep 23 14:33:43 2022 +0200

    chore: no longer uses webpack

 browserslist      |  4 ----
 package.json      | 33 ---------------------------------
 postcss.config.js |  5 -----
 src/main.js       |  3 ---
 webpack.config.js | 55 -------------------------------------------------------
 5 files changed, 100 deletions(-)