Bump dotenv-rails from 2.7.2 to 2.7.4 (#11170)

Bumps [dotenv-rails](https://github.com/bkeepers/dotenv) from 2.7.2 to 2.7.4.
- [Release notes](https://github.com/bkeepers/dotenv/releases)
- [Changelog](https://github.com/bkeepers/dotenv/blob/master/Changelog.md)
- [Commits](https://github.com/bkeepers/dotenv/compare/v2.7.2...v2.7.4)

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

Gemfile.lock

@@ -188,9 +188,9 @@ GEM
       unf (>= 0.0.5, < 1.0.0)
     doorkeeper (5.1.0)
       railties (>= 5)
-    dotenv (2.7.2)
-    dotenv-rails (2.7.2)
-      dotenv (= 2.7.2)
+    dotenv (2.7.4)
+    dotenv-rails (2.7.4)
+      dotenv (= 2.7.4)
       railties (>= 3.2, < 6.1)
     elasticsearch (6.0.2)
       elasticsearch-api (= 6.0.2)