Bump rack-cors from 1.0.3 to 1.0.5

Bumps [rack-cors](https://github.com/cyu/rack-cors) from 1.0.3 to 1.0.5.
- [Release notes](https://github.com/cyu/rack-cors/releases)
- [Changelog](https://github.com/cyu/rack-cors/blob/master/CHANGELOG.md)
- [Commits](cyu/rack-cors@v1.0.3...v1.0.5)

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

Gemfile.lock

@@ -104,7 +104,8 @@ GEM
     pg (1.1.4)
     puma (3.12.1)
     rack (2.0.7)
-    rack-cors (1.0.3)
+    rack-cors (1.0.5)
+      rack (>= 1.6.0)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
     rails (5.2.3)