Update JS dependencies (#15033)

* Update JS dependencies

- Update all JS dependencies
- For octicons, rename trashcan to trash
- For svgo, migrate to v2 api, output seems to have slightly changed but icons look the same
- For stylelint, update config, fix custom property duplicates
- For monaco, drop legacy Edge support
- For eslint, enable new rules, fix new issues
- For less-loader, remove deprecated import syntax

* update svgo usage in generate-images and rebuild logo.svg with it

templates/repo/settings/webhook/base_list.tmpl

@@ -52,7 +52,7 @@
 				<a class="dont-break-out" href="{{$.BaseLink}}/{{.ID}}">{{.URL}}</a>
 				<div class="ui right">
 					<span class="text blue px-2"><a href="{{$.BaseLink}}/{{.ID}}">{{svg "octicon-pencil"}}</a></span>
-					<span class="text red px-2"><a class="delete-button" data-url="{{$.Link}}/delete" data-id="{{.ID}}">{{svg "octicon-trashcan"}}</a></span>
+					<span class="text red px-2"><a class="delete-button" data-url="{{$.Link}}/delete" data-id="{{.ID}}">{{svg "octicon-trash"}}</a></span>
 				</div>
 			</div>
 		{{end}}