Bump rack from 2.0.5 to 2.0.8 (#8)

Bumps [rack](https://github.com/rack/rack) from 2.0.5 to 2.0.8.
- [Release notes](https://github.com/rack/rack/releases)
- [Changelog](https://github.com/rack/rack/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rack/rack/compare/2.0.5...2.0.8)

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

Gemfile.lock

@@ -31,7 +31,7 @@ GEM
     omniauth-oauth2 (1.5.0)
       oauth2 (~> 1.1)
       omniauth (~> 1.2)
-    rack (2.0.5)
+    rack (2.0.8)
 
 PLATFORMS
   ruby