Bump rack from 2.2.4 to 2.2.6.4 in /deprecated/tools/DocCollector

Bumps [rack](https://github.com/rack/rack) from 2.2.4 to 2.2.6.4.
- [Release notes](https://github.com/rack/rack/releases)
- [Changelog](https://github.com/rack/rack/blob/main/CHANGELOG.md)
- [Commits](rack/rack@2.2.4...v2.2.6.4)

---
updated-dependencies:
- dependency-name: rack
  dependency-type: indirect
...

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

deprecated/tools/DocCollector/Gemfile.lock

@@ -34,7 +34,7 @@ GEM
       mini_portile2 (~> 2.8.0)
       racc (~> 1.4)
     racc (1.6.0)
-    rack (2.2.4)
+    rack (2.2.6.4)
     rack-protection (2.2.2)
       rack
     rake (13.0.1)