build(deps): bump bootswatch from v5.3.3 to v5.3.7 in /site

Bumps [bootswatch](https://github.com/thomaspark/bootswatch) from v5.3.3 to v5.3.7.
- [Commits](thomaspark/bootswatch@646c94d...6c4ea3b)

---
updated-dependencies:
- dependency-name: bootswatch
  dependency-version: 6c4ea3bbde9815576d8088436ea6e0032d112740
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

site/Gemfile

@@ -18,7 +18,7 @@ group :jekyll_plugins do
 end
 
 gem 'json'
-gem "bootswatch", github: "thomaspark/bootswatch", tag: "v5.3.3"
+gem "bootswatch", github: "thomaspark/bootswatch", tag: "v5.3.7"
 gem "bootstrap", "~> 5.3.3"
 
 # Windows and JRuby does not include zoneinfo files, so bundle the tzinfo-data gem

site/Gemfile.lock

@@ -1,9 +1,9 @@
 GIT
   remote: https://github.com/thomaspark/bootswatch.git
-  revision: 646c94da2c262473c6f73664f4547c046f3a28dd
-  tag: v5.3.3
+  revision: 6c4ea3bbde9815576d8088436ea6e0032d112740
+  tag: v5.3.7
   specs:
-    bootswatch (5.3.3)
+    bootswatch (5.3.7)
 
 GEM
   remote: https://rubygems.org/