Update to bootstrap 4.5.3

[inktvis75]

Is it possible to upgrade to bootstrap 4.5.3, there are a few fixes in it that I need.

Thank you very much,

Best regards,
Frederik

[RoneoOrg]

I successfully updated to Bootstrap 4.6.1 in two steps:

1. Download the release archive in portio/assets

2. In portio/assets/scss/style.scss, change

   @import "../bootstrap-4.5.2/scss/bootstrap";
   to
   @import "../bootstrap-4.6.1/scss/bootstrap";

[cscetbon]

what about bootstrap 5 ? maybe a PR ?