Bump rack in /tech-docs in the bundler group across 1 directory

Bumps the bundler group with 1 update in the /tech-docs directory: [rack](https://github.com/rack/rack).


Updates `rack` from 2.2.11 to 2.2.12
- [Release notes](https://github.com/rack/rack/releases)
- [Changelog](https://github.com/rack/rack/blob/main/CHANGELOG.md)
- [Commits](rack/rack@v2.2.11...v2.2.12)

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

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

Author: dependabot[bot]

tech-docs/Gemfile.lock

@@ -160,7 +160,7 @@ GEM
     parslet (2.0.0)
     public_suffix (6.0.1)
     racc (1.8.1)
-    rack (2.2.11)
+    rack (2.2.12)
     rack-livereload (0.3.17)
       rack
     rake (13.2.1)