Bump rack from 2.0.5 to 2.0.7

Bumps [rack](https://github.com/rack/rack) from 2.0.5 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@2.0.5...2.0.7)

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

Author: dependabot[bot]

Gemfile.lock

@@ -145,7 +145,7 @@ GEM
       request_store (~> 1.1)
     pg (1.1.3)
     puma (3.12.0)
-    rack (2.0.5)
+    rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
     rails (5.2.1)