Bump rack from 2.0.6 to 2.0.7

Bumps [rack](https://github.com/rack/rack) from 2.0.6 to 2.0.7.
- [Release notes](https://github.com/rack/rack/releases)
- [Changelog](https://github.com/rack/rack/blob/master/CHANGELOG.md)
- [Commits](rack/rack@2.0.6...2.0.7)

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

Gemfile.lock

@@ -22,7 +22,7 @@ GEM
     hashdiff (0.3.8)
     json (2.2.0)
     public_suffix (3.0.3)
-    rack (2.0.6)
+    rack (2.0.7)
     rake (12.3.2)
     rspec (3.8.0)
       rspec-core (~> 3.8.0)