Update to Bootstrap 4.6.1 and use Gulp instead of Grunt

.gitignore

@@ -1,3 +1,5 @@
 /node_modules
 /bower_components
 /tmp
+.sass-cache
+package-lock.json

README.md

@@ -13,24 +13,24 @@ See https://wisvch.github.io/bootstrap-theme/
 ### Setup
 
 Install dependencies using
-[Grunt](http://gruntjs.com) and [Bower](https://github.com/bower/bower) (you must have these
+[Gulp](http://gulpjs.com) and [Bower](https://github.com/bower/bower) (you must have these
 installed).
 
     npm install
     bower install
 
-Now you're ready to go! Simply edit `less/variables.less` and `less/theme.less` to your liking.
-When you're ready, just run `grunt` and it will compile and minify the distribution for you.
-You can also run `grunt watch` to automatically compile as you work.
+Now you're ready to go! Simply edit `sass/variables.less` and `sass/theme.less` to your liking.
+When you're ready, just run `gulp` and it will compile and minify the distribution for you.
+<!-- You can also run `grunt watch` to automatically compile as you work. -->
 
 ### Testing Out
 
 We've provided a "Bootstrap Kitchen Sink" HTML file at `examples/kitchen-sink.html` that contains
 all of the various components in all of their variations. It may not be 100% exhaustive but it
 should give you a good idea of what your theme will look like at a glance.
 
-You can start a development server at `http://localhost:8000` by running `grunt serve`. Your theme will automatically compile while the server is running.
+<!-- You can start a development server at `http://localhost:8000` by running `grunt serve`. Your theme will automatically compile while the server is running. -->
 
 ## Copyright and license
 
-Copyright 2015 W.I.S.V. 'Christiaan Huygens'; copyright 2013 Divshot, Inc. under [the Apache 2.0 license](LICENSE).
+Copyright 2021 W.I.S.V. 'Christiaan Huygens'; copyright 2013 Divshot, Inc. under [the Apache 2.0 license](LICENSE).

_config.yml

@@ -1,6 +1,6 @@
 exclude:
   - README.md
-  - Gruntfile.coffee
+  - gulpfile.js
   - bower.json
   - package.json
   - LICENSE

bower.json

@@ -1,6 +1,6 @@
 {
   "name": "wisvch-bootstrap-theme",
-  "version": "0.0.3",
+  "version": "4.6.1-3",
   "private": false,
   "author": "W.I.S.V. 'Christiaan Huygens'",
   "license": "Apache-2.0",
@@ -18,6 +18,6 @@
     "tests"
   ],
   "dependencies": {
-    "bootstrap": "3.3.5"
+    "bootstrap": "4.6.1"
   }
 }