chore(deps): bump sitemap_generator from 89ec319 to 2b4fc4b

Bumps [sitemap_generator](https://github.com/kjvarga/sitemap_generator) from `89ec319` to `2b4fc4b`.
- [Commits](kjvarga/sitemap_generator@89ec319...2b4fc4b)

---
updated-dependencies:
- dependency-name: sitemap_generator
  dependency-version: 2b4fc4b138e70b675a1eaef62f45d6024f1cb705
  dependency-type: direct:production
...

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

Author: dependabot[bot]

Gemfile.lock

@@ -1,9 +1,9 @@
 GIT
   remote: https://github.com/kjvarga/sitemap_generator.git
-  revision: 89ec319333aaafb2ed12f4a99ce3d664110cfc05
+  revision: 2b4fc4b138e70b675a1eaef62f45d6024f1cb705
   branch: master
   specs:
-    sitemap_generator (6.3.0)
+    sitemap_generator (6.4.0)
       builder (~> 3.0)
 
 GEM